feat(api): ship + research endpoints queue tasks with lead + helpers; mission accept is instant and free (#44)

lib/game/missions.ts

@@ -34,8 +34,12 @@ export interface MissionSystem {
   isCurrent: boolean
 }
 
-// Deterministic per (seed, turn) — same anchoring style as world expansion in save.ts. Every
-// action costs exactly one turn, so the stream never repeats for two different top-ups.
+// Deterministic per (seed, turn) — same anchoring style as world expansion in save.ts.
+// Turn-advancing actions re-anchor the stream, so top-ups on different turns generate
+// different contracts. Mission accept is free and tops up at the current turn, so it may
+// share an anchor with a top-up that already ran at that turn (e.g. the new-game seed at
+// turn 0) — the generated contract can then mirror an existing one: cosmetic, never a
+// double reward (rewards are per row).
 export function missionRng(seed: string, turn: number): () => number {
   return mulberry32((Number(seed) + Math.imul(turn, 0x9e3779b1)) >>> 0)
 }
@@ -152,8 +156,9 @@ export const REWARD_ITEM_NAME = 'MISSION REWARD'
 
 const kindLabel = (kind: ItemKind): string => (kind === 'resource' ? 'RESOURCES' : 'PARTS')
 
-// Accepts an AVAILABLE contract: it becomes THE active mission (one at a time), costs a turn like
-// every other action and writes an event. Returns the fresh board.
+// Accepts an AVAILABLE contract: it becomes THE active mission (one at a time). Instant and
+// free (JC-19) — no turn, no cost; the event is stamped at the current turn. Returns the fresh
+// board.
 export async function acceptMission(db: GameDb, missionId: number): Promise<MissionDto[]> {
   const [save] = await db.db.select().from(schema.saves).limit(1)
   if (!save) throw new MissionError(404, 'No save yet')
@@ -164,10 +169,8 @@ export async function acceptMission(db: GameDb, missionId: number): Promise<Miss
   const active = rows.find((m) => m.state === 'ACTIVE')
   if (active) throw new MissionError(409, `One mission at a time — finish "${active.description}" first`)
 
-  const turn = save.turn + 1
   await db.db.update(schema.missions).set({ state: 'ACTIVE' }).where(eq(schema.missions.id, target.id))
-  await db.db.update(schema.saves).set({ turn }).where(eq(schema.saves.id, save.id))
-  await db.db.insert(schema.events).values({ saveId: save.id, turn, type: 'mission', message: `Accepted mission — ${target.description}`, createdAt: new Date().toISOString() })
+  await db.db.insert(schema.events).values({ saveId: save.id, turn: save.turn, type: 'mission', message: `Accepted mission — ${target.description}`, createdAt: new Date().toISOString() })
   await topUpMissionBoard(db) // one contract left the AVAILABLE list — keep the board topped up
   await persist(db)