Adv 2.0 D&D Phase 12 E3f: Abyss Portal destabilization

§7.6 instability accumulator: +5/day (cap 100), persisted via
TemporalStack. Bands:
  • 0–20   normal
  • 21–40  mild (-1 WIS)
  • 41–60  reality warps (rooms shift order)
  • 61–80  demon surges (12h wandering)
  • 81–99  unraveling — forces 2× supply burn override + -2 all rolls
  • 100    collapse — forced extraction (status = failed)

Pre-burn override fires at 81–99 so the supply doubling lands the same
day the band activates. Collapse at 100 calls completeExpedition
with ExpeditionStatusFailed and emits the AbyssPortalCollapse line.

Adds ReduceAbyssInstability(e, n) for the §7.6 -10 per major story
objective; combat-link wires the call when objectives complete.
Combat-side knobs (WIS/all-roll penalties, room-shift, surge cadence)
are exposed via AbyssInstabilityBandFor — combat-link reads on tick.

Reuses flavor.AbyssPortalDestabilizationMid / Critical / Collapse per
feedback_reuse_existing_flavor.

Closes Phase 12 E3 (Zone Temporal Events). Next session = E4
(Multi-Region Zones).

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

internal/plugin/dnd_expedition_temporal_test.go

@@ -669,6 +669,139 @@ func TestDragonsLair_BossDefeatedSilencesPulses(t *testing.T) {
 	}
 }
 
+func TestAbyssInstabilityBandFor(t *testing.T) {
+	cases := []struct {
+		stack int
+		want  string
+	}{
+		{0, "normal"}, {20, "normal"},
+		{21, "mild"}, {40, "mild"},
+		{41, "warp"}, {60, "warp"},
+		{61, "surges"}, {80, "surges"},
+		{81, "unravel"}, {99, "unravel"},
+		{100, "collapse"},
+	}
+	for _, c := range cases {
+		if got := AbyssInstabilityBandFor(c.stack); got != c.want {
+			t.Errorf("Abyss band(%d) = %q, want %q", c.stack, got, c.want)
+		}
+	}
+}
+
+func TestAbyss_DailyInstabilityIncrements(t *testing.T) {
+	setupZoneRunTestDB(t)
+	uid := id.UserID("@exp-abyss-tick:example")
+	defer cleanupExpeditions(uid)
+
+	exp, err := startExpedition(uid, ZoneAbyssPortal, "",
+		ExpeditionSupplies{Current: 100, Max: 100, DailyBurn: 4, HarshMod: 3})
+	if err != nil {
+		t.Fatal(err)
+	}
+	p := &AdventurePlugin{}
+	// Three briefings → instability should hit 15.
+	for i := 0; i < 3; i++ {
+		fresh, _ := getExpedition(exp.ID)
+		if _, err := db.Get().Exec(
+			`UPDATE dnd_expedition SET last_briefing_at = NULL, supplies_json = ? WHERE expedition_id = ?`,
+			`{"current":99,"max":99,"daily_burn":4,"harsh_mod":3,"foraged_today":false,"packs_standard":3,"packs_deluxe":0}`,
+			exp.ID); err != nil {
+			t.Fatal(err)
+		}
+		fresh, _ = getExpedition(exp.ID)
+		if err := p.deliverBriefing(fresh, time.Now().UTC()); err != nil {
+			t.Fatal(err)
+		}
+	}
+	got, _ := getExpedition(exp.ID)
+	if got.TemporalStack != 15 {
+		t.Errorf("instability = %d, want 15", got.TemporalStack)
+	}
+}
+
+func TestAbyss_UnravelingDoublesBurn(t *testing.T) {
+	setupZoneRunTestDB(t)
+	uid := id.UserID("@exp-abyss-unravel:example")
+	defer cleanupExpeditions(uid)
+
+	exp, err := startExpedition(uid, ZoneAbyssPortal, "",
+		ExpeditionSupplies{Current: 100, Max: 100, DailyBurn: 4, HarshMod: 3})
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Set instability to 85 (unravel band).
+	if _, err := db.Get().Exec(
+		`UPDATE dnd_expedition SET temporal_stack = 85 WHERE expedition_id = ?`,
+		exp.ID); err != nil {
+		t.Fatal(err)
+	}
+	fresh, _ := getExpedition(exp.ID)
+	startSU := fresh.Supplies.Current
+	if err := (&AdventurePlugin{}).deliverBriefing(fresh, time.Now().UTC()); err != nil {
+		t.Fatal(err)
+	}
+	got, _ := getExpedition(exp.ID)
+	wantBurn := float32(8.0) // 4 * 2 (unraveling override)
+	if startSU-got.Supplies.Current != wantBurn {
+		t.Errorf("burn = %v, want %v (unraveling 2×)", startSU-got.Supplies.Current, wantBurn)
+	}
+}
+
+func TestAbyss_CollapseFailsExpedition(t *testing.T) {
+	setupZoneRunTestDB(t)
+	uid := id.UserID("@exp-abyss-collapse:example")
+	defer cleanupExpeditions(uid)
+
+	exp, err := startExpedition(uid, ZoneAbyssPortal, "",
+		ExpeditionSupplies{Current: 100, Max: 100, DailyBurn: 4, HarshMod: 3})
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Set instability to 95 — next daily +5 lands on 100 (collapse).
+	if _, err := db.Get().Exec(
+		`UPDATE dnd_expedition SET temporal_stack = 95 WHERE expedition_id = ?`,
+		exp.ID); err != nil {
+		t.Fatal(err)
+	}
+	fresh, _ := getExpedition(exp.ID)
+	if err := (&AdventurePlugin{}).deliverBriefing(fresh, time.Now().UTC()); err != nil {
+		t.Fatal(err)
+	}
+	got, _ := getExpedition(exp.ID)
+	if got.TemporalStack != 100 {
+		t.Errorf("instability = %d, want 100", got.TemporalStack)
+	}
+	if got.Status != ExpeditionStatusFailed {
+		t.Errorf("status = %q, want %q after collapse", got.Status, ExpeditionStatusFailed)
+	}
+}
+
+func TestReduceAbyssInstability(t *testing.T) {
+	setupZoneRunTestDB(t)
+	uid := id.UserID("@exp-abyss-reduce:example")
+	defer cleanupExpeditions(uid)
+
+	exp, err := startExpedition(uid, ZoneAbyssPortal, "",
+		ExpeditionSupplies{Current: 100, Max: 100, DailyBurn: 4, HarshMod: 3})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := db.Get().Exec(
+		`UPDATE dnd_expedition SET temporal_stack = 25 WHERE expedition_id = ?`,
+		exp.ID); err != nil {
+		t.Fatal(err)
+	}
+	fresh, _ := getExpedition(exp.ID)
+	if got := ReduceAbyssInstability(fresh, 10); got != 15 {
+		t.Errorf("ReduceAbyssInstability(25, 10) = %d, want 15", got)
+	}
+	// Wrong zone — no-op.
+	other := &Expedition{ZoneID: ZoneGoblinWarrens, TemporalStack: 50}
+	if ReduceAbyssInstability(other, 10) != 50 {
+		t.Error("ReduceAbyssInstability on non-Abyss zone should be no-op")
+	}
+}
+
 func TestSunkenTemple_NoTidalOnNonZone(t *testing.T) {
 	setupZoneRunTestDB(t)
 	uid := id.UserID("@exp-tidal-other:example")