chore: remove dead code and fix minor issues (API + infra)

[simple-agent-manager]

Summary

• Delete unused apps/api/src/lib/errors.ts (zero imports — entire codebase uses AppError/errors from middleware/error.ts)
• Remove duplicate requireRouteParam in chat.ts, import from lib/route-helpers.ts instead
• Fix POST /:id/stop returning { status: 'deleted' } → { status: 'stopped' } in nodes.ts
• Remove unused DeploymentState type and DEPLOYMENT_STATE_VERSION constant from scripts/deploy/types.ts
• Fix console.log → console.error for branch fetch failure in CreateWorkspace.tsx
• Use structured JSON logging for trigger execution sync failure in tasks/_helpers.ts
• Add toJSON() to ProviderError so JSON.stringify(error) includes message, provider, statusCode, cause

Not changed

• tools/* in pnpm-workspace.yaml — NOT dead config, tools/og-image has a valid package

Test plan

• pnpm lint passes (0 errors)
• pnpm typecheck passes
• pnpm test passes (all 19 suites, 0 failures)
• Verified errors.ts has zero imports before deletion
• Verified DeploymentState and DEPLOYMENT_STATE_VERSION have zero imports outside their own file

Agent Preflight

• Change class: dead-code-removal, bug-fix
• Impact: Zero risk — dead code deletion, cosmetic log fix, response body correction
• Assumptions: All deletions verified with grep to have zero consumers

🤖 Generated with Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 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