gogobee/gogobee_dnd_session_summary.md

GogoBee D&D Integration — Session Summary

Scope: End-to-end build of the D&D layer from design through audit cleanup, audit fixes, flavor wiring, branding rebrand to "Adv 2.0", and Phase 8 (equipment & damage math). Status: Deploy-ready. 122 D&D tests passing, full suite + vet clean, prod-DB integration verified, root build with -tags goolm clean. Source design: Eleven design docs at the repo root — see gogobee_design_index.md for the canonical list and dependency graph. Phases 1-7 + audit fixes were built from gogobee_dnd_design_doc.md v1.0 / gogobee_dnd_design_doc_v1.1.md (implementation revision); Phase 8 from gogobee_equipment_appendix.md. What's next: Phase 9 — spell system (gogobee_spell_system.md). See the auto-loaded memory entry project_dnd_phase_plan.md for the full Phase 8-16 roadmap.

---

1. Design documents produced

Document	Purpose
gogobee_dnd_design_doc.md (existing v1.0)	Vision document. Untouched.
gogobee_dnd_design_doc_v1.1.md (new)	Implementation revision. Reconciles v1.0 against the actual codebase: real schema, real archetype names, real combat engine. Replaces v1.0's Phase 14 with a smaller-scoped phase plan. Annotated with [REVISED] tags everywhere it diverges from v1.0.
gogobee_dnd_session_summary.md (this file)	Session-wide change log.
gogobee_design_index.md	Canonical map of all 11 design docs + their dependency graph + reading order by intent. New sessions should read this first.

The original design doc treated combat as greenfield. An audit revealed combat_engine.go, combat_bridge.go, combat_stats.go, and combat_narrative.go (~3,500 LOC) already existed in production. v1.1 was rewritten around that constraint: the D&D layer would be additive, not a replacement.

---

2. Phase-by-phase delivery

Phase 1 — Layering proof

• Schema: dnd_character, dnd_abilities, dnd_resources, dnd_combat_state, plus a one-shot adventure_characters_pre_dnd snapshot table populated at deploy as a rollback safety net.
• Nullable D&D columns added to adventure_equipment / adventure_inventory (rarity, stat_bonus_json, attuned).
• Race/class types and tables (7 races, 5 classes), repository functions, stat math (abilityModifier, computeMaxHP, computeAC).
• !setup flow with persistent draft state (pending_setup=1) — survives bot restarts.
• !sheet read-only renderer with archetype-driven inference.

Phase 2 — d20-vs-AC combat

• CombatStats extended with AC and AttackBonus; CombatEvent with Roll and RollAgainst.
• resolvePlayerAttack and resolveEnemyAttack rewritten as d20-vs-AC. Nat 20 = auto-hit + crit, nat 1 = auto-miss tagged "fumble".
• applyDnDPlayerLayer / applyDnDArenaMonsterLayer / applyDnDDungeonMonsterLayer populate AC and attack bonuses based on class/level and threat/tier.
• persistDnDHPAfterCombat writes proportional damage back to the sheet.
• Auto-migration on first combat: legacy players with no dnd_character row get one built from archetype inference + class-tuned standard array. auto_migrated=1 flag enables free !setup rebuild without consuming !respec cooldown.
• Legacy combat ripped out: dual-path branching deleted, DnDMode field removed. Single d20 path for all combat.

Phase 3 — XP, level-up, class passives

• dndXPTable cumulative table anchored to v1.0's design values; dndXPToNextLevel returns segment cost.
• grantDnDXP handles cascading level-ups, recomputes HP max, increments current HP by the gain, sends a level-up DM. Caps cleanly at L20.
• XP grants on every arena and dungeon combat, with near-death win bonuses.
• One class passive per class via applyClassPassives: Fighter +5% damage, Rogue auto-crit-first, Mage +1 attack bonus, Cleric +5 HP heal at low HP, Ranger +5% damage and +1 attack bonus.
• !abilities lists class + race passives. !sheet shows XP progress.

Round 1 — race passives, freeze, respec, subclass stub

• Race passives via applyRacePassives and three new CombatModifiers fields: Halfling Lucky (reroll first nat 1), Orc Rage (+50% damage on first attack after dropping below 50% HP), Dwarf poison resistance (poison ticks halved).
• combat_level freeze: once a player has confirmed a D&D character, checkAdvLevelUp("combat", ...) becomes a no-op. Skill levels (mining/foraging/fishing) keep advancing independently.
• !respec command: 5000 euros, 7-day cooldown via last_respec_at. Auto-migrated chars use the existing free !setup path.
• Subclass-L5 placeholder line added to level-up DM when crossing L5.

Round 2 — Phase 5 (skill checks + NPC wiring)

• 10 skills (Athletics, Acrobatics, Stealth, Arcana, Investigation, Perception, Insight, Persuasion, Intimidation, Deception) with correct stat mapping.
• DC table constants matching D&D 5e (Trivial 5 → Impossible 30).
• performSkillCheck: d20 + ability modifier + race bonus, with nat 20/1 auto-results.
• Race skill bonuses: Half-Elf +1 to all skills, Tiefling +2 on CHA-based.
• !check <skill> [dc] command.
• NPC wiring: passing Insight DC 12 refunds Misty donation; passing Arcana DC 14 refunds Arina investment; passing Persuasion DC 15 grants 10% session shop discount. Silent upside for opted-in players, no UX change for legacy.

Round 3 — Phase 4 (equipment slot mapping + rarity)

• Read-time slot mapping: legacy 5 slots → D&D 10 slots (mapLegacySlot).
• Rarity inference from tier + masterwork + arena tier (inferRarity): Common → Legendary.
• !sheet renders equipment with rarity icons in D&D slot order.
• Full !equip/!unequip/!attune deferred — nothing to populate the new slots yet (legs, hands, rings, amulet) until a future loot pass.

Round 4 — Phase 6 (rest system)

• !rest short: 1h cooldown, 1d6+CON HP recovery (doubled at L5+ per design doc), no daily-action cost.
• !rest long: 24h cooldown, full HP, requires housing (any tier) or pays Thom Krooke inn (200 euros).
• New columns last_short_rest_at, last_long_rest_at on dnd_character.
• Long rest also refreshes all class resources via refreshAllResources.

Round 5 — Phase 7 partial (bestiary)

• Starter bestiary in dnd_bestiary.go: Goblin, Skeleton, Orc Grunt, Troll, Wyvern, Ancient Dragon. Each with HP, AC, attack stats, optional ability, XP value.
• toCombatStats() helper converts a template to the engine's stat shape.
• dndBestiaryByCR(maxCR) for procedural CR-appropriate selection.
• Rival RPS conversion deliberately deferred — the existing rival mini-game is narratively rich and works; the user confirmed leaving it alone.

Round 6 — active abilities + resources

• Pre-arm model (combat is one-shot, so !use mid-fight doesn't fit): !arm <ability> consumes a resource immediately and primes the ability for the next combat. applyArmedAbility fires it via existing CombatModifiers fields and clears the flag.
• Three starter active abilities: Fighter Second Wind, Mage Magic Missile, Cleric Healing Word. Rogue Sneak Attack and Ranger Hunter's Mark stay passive.
• Resource pools per class (stamina, focus, spell_slot, favor) initialized at setup confirm and on auto-migration. Refreshed on long rest.

"Plug the holes" — quality-of-life additions

• !roll <dice> with full NdN+M notation (2d6+3, d20, 4d6-1). Caps at 100 dice × 1000 sides. Single-d20 highlights nat 20 / nat 1.
• !stats — quick ability scores + modifiers + proficiency + AC view.
• !level — level + XP progress with percent-to-next.
• Combat HP scaling: wounded D&D players (sheet HP < max) fight with proportionally reduced legacy combat MaxHP, floor 25%. The rest system finally has gameplay teeth.
• Roll summary line: every fight ends with 🎲 d20 — N/M hit (X crits, Y fumbles). Best: nat 20! injected into arena and dungeon outcome messages without touching protected flavor files.

Onboarding DM

• One-shot welcome DM for legacy players (combat_level >= 2) on first auto-migration. Includes their actual level mapping (Your previous level X is now D&D level Y).
• Triggered via freshMigrate bool returned from ensureDnDCharacterForCombat; only fires the very first time a row is created.
• The full text the user wrote is in dndOnboardingText — TwinBee, Pinkerton agent, divide-by-five, the works.

---

3. Audit + remediation

After all features shipped, four parallel agents audited the D&D layer:

1. Security & player-exploitability
2. Concurrency & data integrity
3. Code quality & correctness
4. Test coverage gaps

Findings consolidated and de-duplicated into 9 actionable items (A through I). All 9 fixed.

ID	Issue	Fix
A	No per-user lock around D&D handlers. Read-modify-write on dnd_character could race.	Acquired existing advUserLock at entry of every top-level D&D mutating command. Internal helpers (called from already-locked combat paths) intentionally stay lock-free.
B	!respec debited euros before saving the wipe. Save failure → euros lost, character intact.	Reordered: balance pre-check → save → resource wipe → debit. Save failure leaves all state intact; debit failure (rare race) grants a free respec rather than a destructive debit.
C	!arm spent resource before saving the armed flag. Save failure → resource wasted.	Reordered: save first → spend. On spend failure, revert armed flag and surface error.
D	Orc Rage threshold used HP < MaxHP/2 integer division — drifted on odd MaxHP.	Replaced with HP*2 < MaxHP. Exact 50% threshold regardless of parity.
E	Respec didn't wipe old class's resource pool (Fighter→Mage left stale stamina rows).	DELETE FROM dnd_resources WHERE user_id = ? in the respec wipe path before the new class initializes via initResources.
F	Onboarding DM re-fired if a player canceled !setup mid-draft and then ran combat.	New onboarding_sent column on dnd_character, set on first successful send, never reset (survives respec, draft cancel, anything).
G	Persuasion shop discount session had no expiry. Player could chain across all purchases.	30-minute TTL from session start (dndPersuasionDiscountTTL). Both pricing and announcement honor the expiry.
H	NPC refund hooks (Misty Insight / Arina Arcana) did separate Load + skill check + Credit. Architecturally fragile.	Covered by Fix A — encounter handlers already hold advUserLock, so the refund's LoadDnDCharacter is safe inside that lock. No code change needed.
I	applyDnDHPScaling lacked a post-scale min(scaled, MaxHP) clamp. Currently safe but fragile.	Added the bounds check defensively.

10 new audit-fix tests added; all pass.

---

4. New files (production)

internal/plugin/dnd.go                  — types, repository, stat math
internal/plugin/dnd_setup.go            — !setup flow, !respec
internal/plugin/dnd_sheet.go            — !sheet, !abilities renderer
internal/plugin/dnd_combat.go           — auto-migration, HP persistence, HP scaling, roll summary
internal/plugin/dnd_passives.go         — class + race passives
internal/plugin/dnd_xp.go               — XP curve, grant, level-up DM
internal/plugin/dnd_skills.go           — skill checks, !check, NPC refund hooks
internal/plugin/dnd_equipment.go        — slot mapping, rarity inference
internal/plugin/dnd_rest.go             — !rest short / long
internal/plugin/dnd_abilities.go        — pre-arm model, resources
internal/plugin/dnd_bestiary.go         — starter monster templates
internal/plugin/dnd_misc_cmds.go        — !roll, !stats, !level
internal/plugin/dnd_onboarding.go       — legacy-player welcome DM

13 new production files, all additive.

5. Modified files

internal/db/db.go                      — schema additions, snapshot logic
internal/plugin/combat_engine.go       — d20 hit resolution (legacy path replaced),
                                         race-passive fields and triggers
internal/plugin/combat_bridge.go       — auto-migrate hook, D&D layer wiring,
                                         class+race passive application,
                                         armed-ability firing, HP persistence,
                                         XP grant, roll summary
internal/plugin/adventure.go           — D&D command routing in OnMessage,
                                         registry entries in Commands(),
                                         roll summary appended to dungeon output
internal/plugin/adventure_arena.go     — roll summary appended to win/death output
internal/plugin/adventure_character.go — combat_level freeze for D&D players
internal/plugin/adventure_npcs.go      — Misty/Arina skill-check refund hooks
internal/plugin/adventure_shop.go      — Persuasion discount session,
                                         price-factor applied at every Debit site,
                                         30-minute TTL
internal/plugin/plugin.go              — Base.SendDM made nil-Client-safe (test support)

6. Test files

internal/db/proddb_integration_test.go         — full migration on real prod DB copy
internal/plugin/dnd_test.go                    — types, math, parsing
internal/plugin/dnd_combat_test.go             — d20 path, monster layers, hit-rate stats
internal/plugin/dnd_round1_test.go             — race passives, combat_level freeze, respec format
internal/plugin/dnd_skills_test.go             — DC table, skill check math
internal/plugin/dnd_equipment_test.go          — slot mapping, rarity inference
internal/plugin/dnd_rest_test.go               — short/long rest mechanics, housing gating
internal/plugin/dnd_abilities_test.go          — resource pool, arm/spend, applyArmed
internal/plugin/dnd_bestiary_test.go           — starter monsters well-formed
internal/plugin/dnd_xp_test.go                 — curve, grant, level-up cascade, L20 cap
internal/plugin/dnd_onboarding_test.go         — message format, threshold, no-panic
internal/plugin/dnd_proddb_integration_test.go — real prod players auto-migrate cleanly
internal/plugin/dnd_plugs_test.go              — HP scaling, roll summary, dice parser
internal/plugin/dnd_audit_fixes_test.go        — all 9 audit findings covered

Total: 90 D&D-layer tests + 1 prod-DB-migration integration test in internal/db.

7. Schema changes

All additive. No drops, no renames.

New tables

dnd_character             -- per-player D&D state (race, class, stats, HP, XP, flags)
dnd_abilities             -- per-ability uses-remaining (reserved for Phase 7+)
dnd_resources             -- per-class resource pools (stamina/focus/mana/favor)
dnd_combat_state          -- active encounter state (reserved)
adventure_characters_pre_dnd  -- one-shot rollback snapshot

New columns on adventure_equipment / adventure_inventory

• dnd_rarity TEXT NOT NULL DEFAULT ''
• dnd_stat_bonus_json TEXT NOT NULL DEFAULT ''
• dnd_attuned INTEGER NOT NULL DEFAULT 0 (equipment only)

New columns on dnd_character

Added incrementally across phases:

• auto_migrated, armed_ability, onboarding_sent
• last_short_rest_at, last_long_rest_at

---

8. New player-facing commands

Command	What it does
!setup	Begin or continue D&D character creation (race / class / stats / confirm)
!setup race <name>	Pick race
!setup class <name>	Pick class
!setup stats <STR> <DEX> <CON> <INT> <WIS> <CHA>	Assign standard array {15,14,13,12,10,8}
!setup confirm	Finalize
!setup cancel	Scrap draft
!sheet	Full character sheet with equipment, treasures, legacy progress
!stats	Ability scores + modifiers + proficiency + AC
!level	Current level + XP progress
!abilities	Class + race passives + active abilities + resource pool
!arm <ability>	Pre-arm an active ability for next combat
!check <skill> [dc]	Roll a skill check
!rest short	Short rest (1h cooldown, partial heal)
!rest long	Long rest (24h cooldown, full heal, requires housing or inn)
!respec	Wipe and rebuild character (5000 euros, 7-day cooldown)
!roll <dice>	Roll arbitrary dice (NdN+M notation)

9. Player-visible behavior changes

• Existing players auto-migrate to a sensible inferred sheet on their next combat — no setup required, no progress lost. They get a one-shot welcome DM with their actual level mapping.
• Combat resolves with d20 + attack bonus vs AC. Every fight ends with a roll summary line.
• Class identity comes through every fight via passives (Fighter +damage, Rogue first-hit auto-crit, Mage attack bonus, Cleric low-HP heal, Ranger +damage and attack).
• Race traits matter: Halfling rerolls one nat 1 per fight, Orc rages at <50% HP, Dwarf takes half poison damage, Half-Elf and Tiefling get skill check bonuses.
• HP carries between fights. A wounded player who skips rest fights at reduced max HP.
• Levels advance based on combat XP. Skill XP (mining/foraging/fishing) advances independently and unaffected.
• Skill checks unlock NPC bonuses: Insight at Misty refunds, Arcana at Arina refunds, Persuasion at the shop grants 10% off for 30 minutes.

10. Level mapping (existing prod players)

Legacy combat_level mapped to D&D level via dndLevelFromCombatLevel = clamp(1, combat_level/5, 20):

Player	Legacy	D&D	Auto-built
holymachina	L49	L9	Dwarf Fighter
prosolis	L28	L5	Human Rogue
quack	L24	L4	Dwarf Fighter
nonk	L20	L4	Human Rogue

Verified end-to-end against a copy of the prod database in data/gogobee.db.

11. What was deliberately deferred or pushed back on

• Rival RPS → D&D combat: confirmed by user to leave alone. The existing mini-game is narratively rich and works.
• Equipment expansion (!equip/!unequip for new D&D slots): nothing to fill rings/amulet/legs/hands until shop or loot expansion. Rendering in !sheet works fine via the read-time mapping.
• Active abilities for Rogue and Ranger: their passives are strong; no actives needed yet.
• Subclass mechanics at L5: placeholder DM only; full content design pending.
• D&D-specific death mechanic: legacy Alive/DeadUntil retained. Sheet HP at 0 means "fight at 25% on next combat, rest to recover" — graceful via Fix #2.
• Closer 5e fidelity (weapon damage dice, saving throws, full spell lists, action economy): per user direction, the d20-flavored adventure feel is the intended ceiling. Approachable beats faithful for a chat bot.
• Dead DodgeRate/CritRate field-population code: cosmetic; not worth regression risk.
• Per-class short-vs-long rest split for resources: all resources currently refresh on long rest only. Cheap follow-up if desired.

11.5 Audit fixes (post-Phase-7)

After all features shipped, four parallel audit agents reviewed the D&D layer. Findings consolidated and de-duplicated into 9 actionable items (A-I), all addressed:

• A — Per-user lock on D&D handlers (reuses existing advUserLock). Prevents double-arm, double-respec, level-up clobbers.
• B — !respec save-then-debit ordering. Save failure no longer destroys euros.
• C — !arm save-then-spend ordering with revert on failure.
• D — Orc Rage threshold off-by-one (HP*2 < MaxHP instead of HP < MaxHP/2).
• E — Resource pool wiped on respec (Fighter→Mage no longer leaves stale stamina rows).
• F — onboarding_sent column for one-shot welcome DM dedup across draft cancel/respec/etc.
• G — Persuasion shop discount expires after 30 minutes.
• H — NPC refund atomicity (covered by Fix A).
• I — applyDnDHPScaling post-clamp.

10 audit-fix tests added.

11.6 Flavor wiring (post-audit)

Five twinbee_*_flavor.go files were sitting in the repo root with conflicting package flavor declarations — never compiled, never wired. Moved to internal/flavor/, fixed one missing-comma syntax error, and wired the player-visible pools that mapped to existing D&D-layer features:

Trigger	Pool	Where it surfaces
Combat starts (arena/dungeon)	flavor.CombatStart	Prepended to first phase message
Player wins (T1-T4 round, dungeon)	flavor.CombatVictory	Italicized in finalMessage
Player wins arena T5 round	flavor.BossDeath	Same slot, boss-specific
Player dies	flavor.PlayerDeath	Appended to death-output
Any nat 20	flavor.Nat20	Roll summary, once per fight
Any nat 1 (no nat 20)	flavor.Nat1	Same slot
Level-up DM	flavor.LevelUp	Italicized prelude after banner
!rest short	flavor.RestShort	Appended
!rest long (housing)	flavor.HomeLongRest	Appended; falls back to RestLong
Misty encounter open	MistyGreeting ∪ legacy	~2× variety
Arina encounter open	ArinaGreeting ∪ legacy	Same
Misty refund pass/fail	MistyInsightSuccess / MistySkillFail	Italicized
Arina refund pass/fail	ArinaArcanaSuccess / ArinaSkillFail	Italicized
Onboarding DM	flavor.ExpeditionStart	Random prelude

Pools deferred to legacy-system migration (harvest events, housing announcements, scheduler tickers, Pete bot) and pools without features (quests, expedition system, traps, save throws, idle/lore chatback) remain unwired pending later phases.

11.7 Branding rebrand: D&D → Adv 2.0 (player-facing only)

Player-visible strings rebranded from "D&D" to "Adv 2.0":

• Command descriptions in Commands() registry (10 commands)
• !setup flow headers
• !sheet and !rest error messages
• Onboarding DM literal level-mapping line
• The deliberate "Dungeons & Drag-" / "d20 System" gag preserved verbatim (it's the joke about being legally distinct)

Internal type names, function names, file names, schema, and code comments still say "D&D" — accurate technical description, no risk to durable state. Full rationale in conversation history.

11.8 Phase 8 — Equipment & damage math

Built per gogobee_equipment_appendix.md (354 lines).

dnd_equipment_profiles.go (new):

• 36 weapons from appendix §2-§3 (10 simple melee, 4 simple ranged, 18 martial melee, 4 martial ranged) with damage dice, types, properties, versatile alt-dies
• 13 armors from appendix §5 (3 light, 5 medium, 4 heavy, 1 shield) with base AC, DEX caps, STR requirements, stealth flags
• dndClassWeaponProficiency and dndClassArmorProficiency per appendix §9 affinity matrix (Rogue's restricted martial list hardcoded)
• rollWeaponDamage(weapon, abilityMod, twoHanded) — real dice roll honoring versatile mode and magic bonus
• computeArmorAC(armor, shield, dexMod) — exact appendix ComputeAC semantics
• Legacy gear synthesis: synthesizeWeaponProfile / synthesizeArmorProfile / synthesizeShield map existing AdvEquipment rows to D&D profiles by tier+name keyword. Masterwork promotes; tier 6+ adds magic bonus up to +3.

combat_engine.go:

• CombatStats extended with Weapon, AbilityModForDamage, WeaponProficient, TwoHandedMode fields. Zero values = backward-compatible.
• resolvePlayerAttack branches: when Stats.Weapon != nil, rolls weapon dice; when nil, legacy calcDamage. Class proficiency penalty (-4 attack) at hit-check time.

dnd_combat.go:

• New applyDnDEquipmentLayer(stats, c, equip) — synthesizes profiles, populates the new fields, recomputes AC. Two-handed weapons forbid shields.
• pickWeaponAbilityMod(weapon, c) — STR for melee non-finesse, DEX for ranged, finesse picks the higher.

combat_bridge.go:

• Both arena and dungeon paths call applyDnDEquipmentLayer after applyDnDPlayerLayer. Equipment-derived AC overrides the placeholder class-armor-floor.

24 new tests covering weapon registry coverage, armor appendix values, ComputeAC math (unarmored, light, medium-capped, heavy, magic bonus), weapon damage roll bounds, versatile two-handed mode, damage floor, class proficiency matrices, legacy gear synthesis (tier mapping, masterwork promotion, high-tier magic), shield name matching, ability mod selection (STR/DEX/finesse), end-to-end equipment layer.

Player-visible balance change for prod players:

User	Class	Synthesized weapon	Damage roll
holymachina	Dwarf Fighter L9	T6+ Greatsword w/ +1 magic	2d6 + STR mod + 1
prosolis	Human Rogue L5	T3-5 Longsword or Shortbow	1d8 + best mod
quack	Dwarf Fighter L4	T3-5 weapon	dice + STR mod
nonk	Human Rogue L4	T3-5 weapon	dice + best mod

Plus AC recomputed from real armor profiles.

Deferred to Phase 8b: magic item slots (rings/amulet), named magic weapons with special properties (Flame Tongue's +2d6 fire, etc.), !equip/!unequip/!attune commands, loot rarity flavor wiring, ammunition tracking, heavy armor STR-requirement penalty.

12. Final state (post-Phase 8)

• Build clean across internal/...
• Root build clean with -tags goolm
• go vet clean across internal/...
• 122 D&D-layer tests + 1 prod-DB migration integration test passing
• All 9 audit findings closed
• Zero modifications to protected internal/flavor/twinbee_*_flavor.go content
• Snapshot rollback table populated; rollback path documented in v1.1 §11.4
• Onboarding flow handles all four prod players cleanly with verified output (now firing on !setup, !check, !stats, !level, !rest, !arm first-touch in addition to combat auto-migration)
• Phase 8 weapon dice + armor AC active for all four prod players on their next combat

13. Next phase: Phase 9 — Spell System

Per the auto-loaded memory entry project_dnd_phase_plan.md and gogobee_design_index.md, Phase 9 implements gogobee_spell_system.md: 79 spells, slots, concentration, !cast command, spell save DCs. Mage/Cleric/Ranger become genuinely playable distinctly.

Architecture commitment from earlier this session: Path C hybrid combat — one-shot for arena/random encounters, turn-based for boss fights only. Phase 9 should preserve approachability outside boss fights; spell mechanics in non-boss combat must fit the pre-arm pattern (consistent with current !arm for active abilities).

Kickoff for next session

Read gogobee_design_index.md and gogobee_spell_system.md cold. Then open
gogobee_dnd_session_summary.md to see what's already shipped. Plan Phase 9
(spell system) per the recommended order in the auto-loaded memory entry.
Show me a tight phase plan before writing any code — what spells, what slots,
what the !cast command flow looks like, how concentration interacts with the
existing one-shot combat (Path C hybrid is locked in). Then once I confirm
scope, build it.

The codebase is deploy-ready. Existing players will see the new system on their next interaction — auto-migrated, onboarded, and never blocked from gameplay regardless of setup state. Phase 9-16 each add depth in a focused session.