fix(orb-broker): return structured 503 on uncaught API errors

[sentry]

Summary

Previously, uncaught exceptions in the /v1/orb/token and /v1/orb/relay/pull API handlers (e.g., during request body stream reading or database lookups) would bypass existing error handling. This caused the framework to return raw HTTP 500 responses, which the client interpreted as orb_broker_unavailable. This change wraps the entire body of these handlers in a top-level try-catch block. Now, any unhandled exceptions within these handlers will result in a structured HTTP 503 response with a broker_error payload, and a orb_broker_request_failed error log. This provides more consistent and actionable error responses for self-hosted Gittensory instances, allowing for proper retry and dead-letter queue handling.

Scope

• The PR title follows type(scope): short summary Conventional Commit format, for example fix(api): restore profile access checks.
• This PR is focused and does not mix unrelated backend, UI, MCP, docs, dependency, and deploy changes.
• This follows CONTRIBUTING.md and does not reintroduce GitHub Pages, VitePress, site/, or CNAME.
• I linked an issue, or this is small enough that the summary explains why an issue is not needed.

Validation

• git diff --check
• npm run actionlint
• npm run typecheck
• npm run test:coverage locally; codecov/patch requires ≥99% coverage of the lines AND branches you changed (aim for 100% on your diff so CI variance does not fail near the threshold). Global coverage is a non-blocking trend with a loose 90% backstop, not the gate.
• npm run test:workers
• npm run build:mcp
• npm run test:mcp-pack
• npm run ui:openapi:check
• npm run ui:lint
• npm run ui:typecheck
• npm run ui:build
• npm audit --audit-level=moderate
• New or changed behavior has unit/integration tests for new branches, fallback paths, and sanitizer boundaries

If any required check was skipped, explain why:

Safety

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• Auth, cookie, CORS, GitHub App, Cloudflare, or session changes include negative-path tests.
• API/OpenAPI/MCP behavior is updated and tested where needed.
• UI changes use live API data or real empty/error/loading states, not production mock/demo fallbacks.
• Visible UI changes include a UI Evidence section below with JPG/JPEG or PNG screenshots arranged as organized, captioned, clickable thumbnails. SVG screenshots are not used as review evidence. Review-only screenshots or recordings are not committed to the repository.
• Public docs/changelogs are updated where needed; changelogs are only edited for release-prep PRs.

UI Evidence

Required for visible UI, frontend, docs, or extension changes. Attach GitHub-hosted JPG/JPEG or PNG screenshots here; SVG screenshots are not accepted as review evidence. Use a compact table/grid of clickable thumbnails with a short state/title such as "Loaded state", "Empty state", "Error state", "Mobile layout", or "PR sidebar". Prefer annotated screenshots with a colored box, outline, arrow, or highlighter showing what changed. Recordings can be supplemental, but screenshots are still expected for visual review. Do not commit review-only screenshots, recordings, or docs/review-evidence/** files.

State / title	JPG/PNG evidence
Loaded state	<a href="FULL_URL.png"><img src="FULL_URL.png" alt="Loaded state" width="240"></a>
Empty/error/mobile state, if relevant

Notes

Fixes GITTENSORY-J

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[codecov]

Codecov Report

❌ Patch coverage is 72.41379% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.45%. Comparing base (102ca62) to head (b7e158f).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/api/routes.ts	72.41%	7 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3418      +/-   ##
==========================================
- Coverage   93.46%   93.45%   -0.02%     
==========================================
  Files         291      291              
  Lines       30790    30798       +8     
  Branches    11221    11223       +2     
==========================================
+ Hits        28779    28781       +2     
- Misses       1355     1361       +6     
  Partials      656      656              

Files with missing lines	Coverage Δ
src/api/routes.ts	94.56% <72.41%> (-0.29%)	⬇️

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[loopover-orb]

Gittensory is closing this pull request on the maintainer's behalf (CI is failing (codecov/patch)). This is an automated maintenance action — to pursue this change, please open a new pull request with the issues resolved. Closed PRs may be analyzed later to improve review accuracy, but they are not automatically reopened or re-reviewed.