[AAASM-2309] ✨ (scenarios): Add approval-gates/node/ TypeScript implementation

[Chisanan232]

What changed

Adds the Node.js/TypeScript sub-project for the scenarios/approval-gates/ scenario. Reads policy.yaml to find rules, evaluates approval_required decisions via MockApprovalClient, and demonstrates the full pending → approved → executed cycle.

Files added (scenarios/approval-gates/node/):

• src/approval.ts — loads ../policy.yaml, MockApprovalClient, evaluate() handles allow / deny / approval_required
• src/tools.ts — getBalance (ALLOWED immediately), transferFunds (requires approval)
• src/index.ts — main demo showing the approval cycle with formatted output
• tests/smoke.test.ts — 12 vitest tests: policy rules, mock client approve/reject, evaluate outcomes, tool outputs

Related ticket

Closes AAASM-2309

How to verify

cd scenarios/approval-gates/node
pnpm install
pnpm start      # shows pending → approved → executed
pnpm test       # 12 tests pass

Checklist

• PR title follows [AAASM-XXXX] <GitEmoji> (<scope>): <summary>
• No secrets, API keys, or .env files committed
• Example sub-projects include their own README via the scenario-level README
• SDK/runtime version dependencies are documented or pinned

[sonarqubecloud]

Quality Gate passed

Issues
8 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Chisanan232]

Code Review — Claude Code

CI status

Check	Result
build	✅ pass
run	✅ pass
SonarCloud	✅ pass

All checks green.

Scope completeness

Verified against AAASM-2309 ticket requirements. All 7 expected Node.js files are present:

• scenarios/approval-gates/node/package.json ✅
• scenarios/approval-gates/node/tsconfig.json ✅
• scenarios/approval-gates/node/src/tools.ts ✅
• scenarios/approval-gates/node/src/approval.ts — MockApprovalClient, evaluate() handling allow/deny/approval_required ✅
• scenarios/approval-gates/node/src/index.ts ✅
• scenarios/approval-gates/node/tests/smoke.test.ts — 12 tests ✅
• scenarios/approval-gates/node/pnpm-lock.yaml ✅

Note on diff size: The PR diff currently includes approval-gates Python and shared files from PR #33 because this branch was stacked on top of it. The extra files disappear once PR #33 merges to master. The net-new scope is solely the node/ directory.

Code quality notes

• evaluate() handles all three policy actions in a single typed function — clean discriminated union return type ✅
• MockApprovalClient(false) rejection path covered by tests ✅
• js-yaml loaded with { schema: yaml.CORE_SCHEMA } — prevents arbitrary code execution via !!js/function tags ✅
• 12 tests: policy rules, client approve/reject, evaluate outcomes, tool outputs ✅

Verdict

✅ Ready to merge (after PR #33 merges first). All CI green, AAASM-2309 scope fully covered.