fix(ai): background generation cannot spend the interactive day

The automatic generators — status and reference cards, the briefing, the
arrival reaction, the nudge, document summaries and the index backfill —
reserved against the same ceiling as the chat. On the operator's account
that meant 150-330 ledger rows a day, 172 metric generations before
06:42Z, and a ceiling already spent when he opened the chat.

Every background surface now reserves through
`resolveDailyCapFor("job", chain)`: half the cost owner's ceiling, all
job surfaces together. The interactive routes keep the whole ceiling, so
a day of background work can no longer take the user's own away.

src/app/api/labs/ocr/extract/__tests__/route.test.ts

@@ -45,6 +45,7 @@ vi.mock("@/lib/ai/coach/budget", () => ({
   reserveBudget: vi.fn(),
   reconcileSpend: vi.fn().mockResolvedValue(undefined),
   resolveDailyCap: vi.fn(() => 200_000),
+  resolveDailyCapFor: vi.fn(() => 200_000),
   resolveCostOwner: vi.fn(() => "operator" as const),
 }));
 vi.mock("@/lib/labs/ocr-extract", async () => {