refactor: tick pipeline pattern — read all → compute all → write all (issue #103)

- New tick-pipeline.ts: TickContext/TickWrites types + buildTickContext/applyTickWrites orchestrator
- gameStore.ts tick(): refactored to 3-phase pipeline (read snapshot → compute updates → batch writes)
- combat-actions.ts: accept signedPacts as parameter instead of usePrestigeStore.getState() in combat loop
- combatStore.ts/combat-state.types.ts: updated processCombatTick signature for signedPacts passthrough
- craftingStore.ts: removed tempState = { ...get(), rawMana } as any anti-pattern
- preparation-actions.ts: accept rawMana as explicit parameter instead of GameState bag

docs/project-structure.txt

@@ -312,6 +312,7 @@ Mana-Loop/
 │       │   │   ├── index.ts
 │       │   │   ├── manaStore.ts
 │       │   │   ├── prestigeStore.ts
+│       │   │   ├── tick-pipeline.ts
 │       │   │   └── uiStore.ts
 │       │   ├── types/
 │       │   │   ├── attunements.ts