docs: add agent budget enforcement gates

[catcherintheroad-hub]

Created from review issue: #1380

Summary

• Add resource budget enforcement evidence gates to the agent architecture review.
• Require quota scope, shared cost ledger, retry/fallback accounting, concurrency limits, sub-agent budget inheritance, fail-closed behavior, alerts, and kill switch evidence.
• Add edge-case fixtures for per-request-only limits, retry/fallback metering bypass, sub-agent fan-out, and complete shared-ledger enforcement.

Validation

• git diff --check
• Markdown fence/non-ASCII sanity check
• Reference URL checks for OWASP LLM Top 10, NIST AI RMF, and OWASP GenAI

[chatgpt-codex-connector]

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Reviewed commit: 6b9770ebaa

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[chatgpt-codex-connector]

Add Budget Enforcement to finding Review Area options

When Step 2A produces a budget-related finding, reports that follow this template have no matching Review Area value in the Findings section above, even though this new summary row now treats Budget Enforcement as a first-class area. This makes the generated assessment internally inconsistent for the new high-severity cases; please add Budget Enforcement to the Finding Review Area options as well.

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