feat(candidate-execution): enforce aggregate token grants

[drewstone]

Summary

• Add an optional maxTotalTokens cap to the direct protected model-grant port.
• Preserve Router accountedInputTokens and require usageWithinLimits: true before Runtime accepts a terminal receipt.
• Retain expired reservation state for terminal recovery validation.
• Keep signed execution-plan evidence on the Interface 0.47 schema; the new field is not added to signed plans until Interface publishes it.

Proof

• pnpm test: 2,593 passed, 6 skipped (2,599 tests).
• pnpm run typecheck: passed.
• pnpm run lint: passed.
• pnpm run verify:package: passed.
• pnpm run docs:freshness: passed.
• pnpm run verify:static-imports: passed.
• pnpm run check:model-execution-boundary: passed.
• pnpm run check:testing-fixture: passed.
• pnpm run check:version-bump: passed for 0.133.6.
• No provider calls or spend.

[tangletools]

✅ Auto-approved drewstone PR — 4cb6aa89

This PR was opened by the trusted drewstone account.
The full PR reviewer audit still runs separately and will publish findings if it detects issues.

_{tangletools · auto-approval · reason: drewstone_author · 2026-08-13T16:23:48Z}