Four anchor holidays (Hallowtide, Midwinter Feast, Sweethearts' Revel,
First Bloom) each get a 7-day window (anchor ±3 days) that layers three
things on the world, all reusing existing machinery:
1. A themed Omen that overrides the weekly rotation. Reuses the B3 omen
effect fields, so the non-combat rule holds; kept behind activeOmen's
simOmenDisabled guard (and activeSeason honours it too) so no season
path can reach the balance sim or move the golden.
2. A curated curio shelf at Luigi's — existing registry items rotated to
the front of dailyCuriosStock, so no net-new power enters the economy.
Off-season output is byte-identical to before.
3. A themed road visitor via the ambient seam — a season_visitor event
that leaves a sellable keepsake + coin gift. No combat: the ambient
seam still never opens a fight.
Pure function of the UTC date + anchor calendar — no schema, ticker, or
persistence, same discipline as the Omen and holiday calendar. Season
banner rides the existing morning DM (no net-new scheduled message).
go test ./internal/plugin ./internal/db green; combat golden byte-identical.
Claude-Session: https://claude.ai/code/session_017mEwUmmS7aQTP2NQXj6rUa
activeOmen() is a pure function of the UTC ISO (year, week): omenTable
indexed by (year*53+week)%len, so it advances weekly with no schema, no
ticker state, no persistence. Five non-combat seams read it — harvest yield,
supply freebie, expedition start mood, arena payout (scales gross earnings
before the pot tax), and ingredient drop chance. TwinBee reveals the active
omen in the existing morning DM (no net-new scheduled message).
Launch set is buffs-with-texture on non-combat levers only: Bountiful
Harvest, Quartermaster's Blessing, Golden Purse, Overflowing Satchels, Still
Waters. Nothing touches SimulateCombat or the turn engine — the omen is keyed
on the real clock, so a combat mutator would make the golden and the balance
corpus week-dependent. The plan's "elites +2 ATK" is deliberately dropped for
that reason.
The balance sim drives the real expedition loop and would otherwise traverse
all five seams, making corpus sweeps depend on the wall-clock week. NewSimRunner
sets simOmenDisabled (mirrors simAutoArmEnabled), so activeOmen returns a
no-effect omen under the sim. Still Waters subtracts from the daily threat
*rise* only, floored at hold-steady — it never forces active decay.
Claude-Session: https://claude.ai/code/session_017mEwUmmS7aQTP2NQXj6rUa
