feat(auth): add signIn rate-limit backfill with dual ip/account budgets

Wires the rate-limit primitive end-to-end through auth.signIn as the
canonical credential-stuffing defence example:

- manifest: rateLimit [ip 5/1m, account 10/1h] on signIn use case
- use case: rateLimit: IRateLimit dep; dual consume + TooManyRequestsError
- binders: ctx.rateLimit ?? new NoopRateLimit() in bind-production + bind-dev-seed
- tRPC: TooManyRequestsError → TOO_MANY_REQUESTS error code in authProcedure
- tests: RecordingRateLimit dual-consume assertion; InMemoryRateLimit
  budget-1 ip + account rejection; coverage 100% on use-cases layer
- ESLint: _manifest-ast.js extractRateLimitNames handles RateLimitBudget
  objects ({name,window,budget}) in addition to plain string literals,
  no-undeclared-rate-limit passes on both "ip" and "account" call sites

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/auth/src/integrations/api/procedures.ts

@@ -5,6 +5,7 @@ import {
   AuthenticationError,
   UnauthenticatedError,
   UnauthorizedError,
+  TooManyRequestsError,
 } from "../../entities/errors/auth";
 import { InputParseError } from "../../entities/errors/common";
 
@@ -14,5 +15,6 @@ export const authProcedure = t.procedure.use(
     [AuthenticationError, "UNAUTHORIZED"],
     [UnauthenticatedError, "UNAUTHORIZED"],
     [UnauthorizedError, "FORBIDDEN"],
+    [TooManyRequestsError, "TOO_MANY_REQUESTS"],
   ]),
 );