feat(core-shared): add withRateLimit wrapper and conformance enforcement

- Add withRateLimit(rateLimit, fn) in rate-limit/with-rate-limit.ts,
  attaching the RateLimited brand at DI bind time
- Extend wireUseCase to accept optional rateLimit?: IRateLimit and
  compose withRateLimit innermost (before analytics/audit); propagate
  __rateLimited through analytics + audit inline wrappers
- Extend withSpan and withCapture PROPAGATED_BRANDS to include
  __rateLimited so the outermost binding carries the brand
- Extend assertFeatureConformance to require __rateLimited brand when
  manifest.useCases[name].rateLimit.length > 0; refactored into
  helper functions to stay within complexity thresholds
- Add rateLimit?: IRateLimit to BindContext; default to NoopRateLimit
  in web-next bindAllProduction and bindAllDevSeed aggregators
- Unit tests for withRateLimit brand attachment, factory passthrough,
  and composition; synthetic fixture tests for conformance errors

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

packages/core-shared/src/instrumentation/with-span.ts

@@ -7,6 +7,7 @@ const PROPAGATED_BRANDS = [
   "__audited",
   "__analyzed",
   "__consentChecked",
+  "__rateLimited",
 ] as const;
 
 export function withSpan<Args extends unknown[], R, Extra extends object>(