Adv 2.0 D&D Phase R R3-R5: Combat-link, zone loot, fishing, economy

R3 — Combat Event Integration:
- dnd_expedition_combat.go: Combat Interrupt rolls (§4.2) with
  threat-clock and Ranger-wilderness modifiers; Patrol Encounters
  scaled by threat level; recordZoneKill writer with monsterKillTags.
- Interrupt gate at head of handleHarvestCmd; patrol gate before
  resolveRoom in zoneCmdAdvance; kill writer wired into combat-win
  paths.

R4a — Zone Loot Tables:
- dnd_zone_loot.go: §5 loot drop tables for all 10 zones × 5 tiers
  with §8.1 sell-value bands. dropTierFromCR brackets + boss floor.
- Hooks on combat-win in resolveCombatRoom, resolveBossRoom,
  runHarvestInterrupt, tryPatrolEncounter.

R4b — Fishing Integration:
- dnd_zone_fish.go: fishingZones allow-list, fishingSkillBonus,
  rangerRareCatchUpgrade (§6.2), feywildFishDistortion narration.
- §6.1 fish entries added to resource registry for Forest, Sunken
  Temple, Underdark, Feywild zones.
- !fish wired through handleHarvestCmd; zoneItemFlavor matrix
  populated for all 10 zones × all loot items.

R5 — Economy Integration:
- dnd_economy.go: !sell (post-expedition gate, single CHA Persuasion
  DC 17 → +15% bump), !craft (§8.2 4 exemplar recipes), !lore
  (INT/Arcana DC 15 recipe discovery).
- dnd_known_recipe table for persistent recipe discovery.

Flavor reuse: HarvestInterrupt, PatrolEncounter, CombatVictory,
PlayerDeath, LootDrop*, FeywildTimeDistortion* — all existing pools.
No new flavor file.

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

internal/plugin/dnd_zone_loot_test.go

@@ -0,0 +1,172 @@
+package plugin
+
+import (
+	"math/rand/v2"
+	"testing"
+)
+
+// ── §5 Drop tier brackets ──────────────────────────────────────────────────
+
+func TestDropTierFromCR_Brackets(t *testing.T) {
+	cases := []struct {
+		name           string
+		cr             float32
+		isBoss         bool
+		wantGuaranteed LootTier
+		wantBonus      LootTier
+		wantDropChance float64
+	}{
+		{"low cr no guarantee", 0.5, false, LootTierCommon, "", 0.70},
+		{"cr 1 still common only", 1.0, false, LootTierCommon, "", 0.70},
+		{"cr 2 guarantees common", 2.0, false, LootTierCommon, LootTierUncommon, 1.0},
+		{"cr 5 uncommon", 5.0, false, LootTierUncommon, LootTierRare, 1.0},
+		{"cr 9 rare", 9.0, false, LootTierRare, LootTierEpic, 1.0},
+		{"cr 13 epic", 13.0, false, LootTierEpic, LootTierLegendary, 1.0},
+		{"boss min rare", 4.0, true, LootTierRare, LootTierEpic, 1.0},
+		{"high cr boss still rare floor", 20.0, true, LootTierRare, LootTierEpic, 1.0},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			g, b, _, dc := dropTierFromCR(c.cr, c.isBoss)
+			if g != c.wantGuaranteed || b != c.wantBonus || dc != c.wantDropChance {
+				t.Errorf("got (%s,%s,%g) want (%s,%s,%g)",
+					g, b, dc, c.wantGuaranteed, c.wantBonus, c.wantDropChance)
+			}
+		})
+	}
+}
+
+// ── Loot table coverage ─────────────────────────────────────────────────────
+
+func TestZoneLootTables_AllZonesAllTiers(t *testing.T) {
+	zones := []ZoneID{
+		ZoneGoblinWarrens, ZoneCryptValdris, ZoneForestShadows,
+		ZoneSunkenTemple, ZoneManorBlackspire, ZoneUnderforge,
+		ZoneUnderdark, ZoneFeywildCrossing, ZoneDragonsLair, ZoneAbyssPortal,
+	}
+	tiers := []LootTier{
+		LootTierCommon, LootTierUncommon, LootTierRare, LootTierEpic, LootTierLegendary,
+	}
+	for _, z := range zones {
+		table, ok := zoneLootTables[z]
+		if !ok {
+			t.Errorf("zone %s missing loot table", z)
+			continue
+		}
+		for _, tier := range tiers {
+			if len(table[tier]) == 0 {
+				t.Errorf("zone %s has empty %s slate", z, tier)
+			}
+		}
+	}
+}
+
+func TestZoneLootTables_SellValuesInRarityBrackets(t *testing.T) {
+	bands := map[LootTier][2]int{
+		LootTierCommon:    {5, 15},
+		LootTierUncommon:  {25, 60},
+		LootTierRare:      {100, 300},
+		LootTierEpic:      {500, 1200},
+		LootTierLegendary: {3000, 10000},
+	}
+	for zid, table := range zoneLootTables {
+		for tier, slate := range table {
+			lo, hi := bands[tier][0], bands[tier][1]
+			for _, e := range slate {
+				if e.BaseValue < lo || e.BaseValue > hi {
+					t.Errorf("zone %s tier %s item %s value %d outside [%d,%d]",
+						zid, tier, e.Name, e.BaseValue, lo, hi)
+				}
+			}
+		}
+	}
+}
+
+// ── rollZoneLoot behavior ───────────────────────────────────────────────────
+
+func TestRollZoneLoot_LowCRRespectsDropChance(t *testing.T) {
+	// CR 0.5 has 70% drop chance — over many rolls we should see misses.
+	rng := rand.New(rand.NewPCG(1, 2))
+	misses := 0
+	hits := 0
+	for i := 0; i < 1000; i++ {
+		_, _, ok := rollZoneLoot(ZoneGoblinWarrens, 0.5, false, rng)
+		if ok {
+			hits++
+		} else {
+			misses++
+		}
+	}
+	if misses == 0 {
+		t.Errorf("expected some misses at CR 0.5, got 0/%d", hits+misses)
+	}
+	if hits == 0 {
+		t.Errorf("expected some hits at CR 0.5, got 0/%d", hits+misses)
+	}
+}
+
+func TestRollZoneLoot_BossAlwaysDropsRareOrBetter(t *testing.T) {
+	rng := rand.New(rand.NewPCG(7, 9))
+	for i := 0; i < 200; i++ {
+		_, tier, ok := rollZoneLoot(ZoneAbyssPortal, 20, true, rng)
+		if !ok {
+			t.Fatalf("boss drop missed (i=%d)", i)
+		}
+		if tier != LootTierRare && tier != LootTierEpic {
+			t.Fatalf("boss tier = %s, want Rare or Epic", tier)
+		}
+	}
+}
+
+func TestRollZoneLoot_HighCROccasionallyUpgradesToLegendary(t *testing.T) {
+	rng := rand.New(rand.NewPCG(11, 13))
+	saw := false
+	for i := 0; i < 5000; i++ {
+		_, tier, ok := rollZoneLoot(ZoneDragonsLair, 15, false, rng)
+		if ok && tier == LootTierLegendary {
+			saw = true
+			break
+		}
+	}
+	if !saw {
+		t.Errorf("expected at least one Legendary upgrade at CR 15 over 5000 rolls")
+	}
+}
+
+func TestRollZoneLoot_UnknownZoneReturnsFalse(t *testing.T) {
+	rng := rand.New(rand.NewPCG(1, 1))
+	_, _, ok := rollZoneLoot(ZoneID("nonexistent_zone"), 5, false, rng)
+	if ok {
+		t.Errorf("expected ok=false for unknown zone")
+	}
+}
+
+// ── Zone-contextual flavor ──────────────────────────────────────────────────
+
+func TestZoneItemDescription_PotionOfHealingAllZones(t *testing.T) {
+	zones := []ZoneID{
+		ZoneGoblinWarrens, ZoneCryptValdris, ZoneForestShadows,
+		ZoneSunkenTemple, ZoneManorBlackspire, ZoneUnderforge,
+		ZoneUnderdark, ZoneFeywildCrossing, ZoneDragonsLair, ZoneAbyssPortal,
+	}
+	for _, z := range zones {
+		desc := zoneItemDescription(z, "Potion of Healing")
+		if desc == "" {
+			t.Errorf("zone %s has no Potion of Healing flavor", z)
+		}
+	}
+}
+
+func TestZoneItemDescription_NonMatchingItemReturnsEmpty(t *testing.T) {
+	if got := zoneItemDescription(ZoneGoblinWarrens, "Random Junk"); got != "" {
+		t.Errorf("expected empty for unmapped item, got %q", got)
+	}
+}
+
+func TestLootFlavorLine_AllTiersPickSomething(t *testing.T) {
+	for _, tier := range []LootTier{LootTierCommon, LootTierUncommon, LootTierRare, LootTierEpic, LootTierLegendary} {
+		if got := lootFlavorLine(tier); got == "" {
+			t.Errorf("tier %s produced empty flavor line", tier)
+		}
+	}
+}