Adv 2.0 D&D layer: Phases 1-8 + Phase 9 SP1+SP2

Combines all uncommitted D&D work into one checkpoint:

Phases 1-8 (per gogobee_dnd_session_summary.md):
- Race/class/stats system, !setup flow, !sheet, !respec
- d20-vs-AC combat with race/class passives, auto-migration
- XP/level-up, skill checks, NPC refund hooks
- Equipment slot mapping, rarity, !rest short/long
- Pre-arm active abilities, resource pools
- Bestiary, !roll/!stats/!level, onboarding DM
- Audit fixes A-I, flavor wiring under internal/flavor/
- Phase 8 weapon dice + armor AC tables (gogobee_equipment_appendix)

Phase 9 SP1 — spell system foundations:
- 79 SpellDefinitions (76 in-scope + 3 reaction-deferred)
- dnd_known_spells, dnd_spell_slots tables
- pending_cast / concentration_* columns on dnd_character
- Slot tables for Mage/Cleric/Ranger, DC + attack-bonus math
- Long-rest refreshes slots; respec wipes spell state
- Auto-grant default known list on !setup confirm and auto-migration

Phase 9 SP2 — !cast / !spells / !prepare commands:
- Out-of-combat HEAL and UTILITY resolve immediately
- Damage/control/buff queue as pending_cast for next combat
- Audit-style save-then-debit, slot refund on save failure
- !cast --drop, concentration supersession, prep-cap enforcement
- Reaction spells refused with Phase 11 note

SP3 (combat-time resolution of pending_cast) and SP4 (full prep/learn
tests) are next. Build clean, full test suite green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/plugin/coop_dungeon_db.go

@@ -192,6 +192,31 @@ func unlockCoopCombatActionsForRun(runID int) error {
 	return err
 }
 
+// activeCoopMemberSet returns the set of user IDs currently locked into an
+// active co-op run. The midnight reset uses this to skip the streak/babysit
+// logic for those players — their co-op participation auto-resolves daily,
+// so they should not be treated as idle even though they take no manual
+// actions.
+func activeCoopMemberSet() (map[string]bool, error) {
+	d := db.Get()
+	rows, err := d.Query(`SELECT m.user_id FROM coop_dungeon_members m
+		JOIN coop_dungeon_runs r ON r.id = m.run_id
+		WHERE r.status = 'active'`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := map[string]bool{}
+	for rows.Next() {
+		var u string
+		if err := rows.Scan(&u); err != nil {
+			return nil, err
+		}
+		out[u] = true
+	}
+	return out, rows.Err()
+}
+
 func lockCoopCombatActions() error {
 	d := db.Get()
 	_, err := d.Exec(`UPDATE adventure_characters