fix(orb): return 503 instead of a bare 500 from the relay register/pull routes

[JSONbored]

Summary

• Fixes fix(orb): drainOrbRelay returns HTTP 500 repeatedly (872 Sentry events, escalating) #4995: drainOrbRelay returned HTTP 500 repeatedly (872 Sentry events, escalating).
• Root cause was not what Sentry Seer suggested. Seer proposed adding an in-flight guard and fixing a timeout/poll-interval mismatch — both already exist and are already correct (drainInFlight guard in src/server.ts, and the 30s poll interval is explicitly matched to drainOrbRelay's own 30s AbortSignal.timeout, per that code's own comment). The real gap was entirely server-side: /v1/orb/relay/register and /v1/orb/relay/pull both call DB-touching functions (validateOrbRelayEnrollment, registerValidatedOrbRelay, pullRelayPending) with no error handling of their own. An unhandled D1/Postgres error inside either one escaped as a bare framework 500 — exactly the class of gap #orb-broker-500 already closed for /v1/orb/token's own DB-touching call, just never applied to these two sibling routes.
• Fix: .catch(...) on just the two DB-touching calls per handler (not a big try/catch wrapping the whole handler), so pre-existing logic/branches keep their original indentation and coverage — genuine DB failures now return a clean 503 { error: "broker_error" }.

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 a currently open issue this PR resolves (Closes #4995).

Validation

• git diff --check
• npm run actionlint
• npm run typecheck
• npm run test:coverage locally
• npm run test:workers
• npm run build:mcp
• npm run test:mcp-pack
• npm run ui:openapi:check (confirms these internal broker routes aren't part of the public OpenAPI surface — no drift)
• 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:

• test:coverage (full unsharded): not run end-to-end — ran scoped vitest --coverage for test/integration/orb-relay.test.ts and confirmed via lcov that every line/branch in this diff (both the register and pull handlers' new .catch() paths, including the error instanceof Error vs String(error) branch) is covered — including a second regression test per handler after the first pass showed one call site's error path was untested. The one remaining zero-hit branch in the surrounding function is confirmed pre-existing (same branch was already 0% covered before this diff, verified via git stash) and structurally unreachable at this call site given RegisterResult's real producers — not introduced by this change.
• test:workers / build:mcp / test:mcp-pack / ui:lint / ui:typecheck / ui:build: not run — this change touches only src/api/routes.ts and its integration test; no Worker-pool, MCP, or UI-component surface changed.

Safety

• No secrets, wallet details, hotkeys, coldkeys, user PATs, private keys, raw trust scores, private rankings, or private maintainer evidence are exposed.
• Public GitHub text stays sanitized, low-noise, and does not imply compensation guarantees or optimization tactics.
• Auth, cookie, CORS, GitHub App, Cloudflare, or session changes include negative-path tests. (These are broker-auth routes — negative paths (401/403/413/503) are all covered, including the two new 503 regression tests.)
• API/OpenAPI/MCP behavior is updated and tested where needed. (Checked — not part of the public OpenAPI surface.)
• UI changes use live API data or real empty/error/loading states. (N/A.)
• Visible UI changes include a UI Evidence section. (N/A.)
• Public docs/changelogs are updated where needed. (N/A — internal engine behavior; changelog is not edited in a normal PR.)

Notes

Part of a batch of 13 bug fixes filed from a Sentry-issue triage this session (#4994–#5006). This is #2 by impact.

[superagent-security]

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.36%. Comparing base (445c9fc) to head (be7a825).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5017   +/-   ##
=======================================
  Coverage   94.35%   94.36%           
=======================================
  Files         457      457           
  Lines       39216    39228   +12     
  Branches    14300    14306    +6     
=======================================
+ Hits        37004    37016   +12     
  Misses       1558     1558           
  Partials      654      654           

Flag	Coverage Δ
shard-1	46.49% <0.00%> (-0.29%)	⬇️
shard-2	33.66% <0.00%> (+0.25%)	⬆️
shard-3	31.38% <100.00%> (+0.34%)	⬆️
shard-4	32.60% <0.00%> (-0.57%)	⬇️
shard-5	34.48% <0.00%> (+0.99%)	⬆️
shard-6	45.34% <0.00%> (+0.18%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/api/routes.ts	94.28% <100.00%> (+0.03%)	⬆️

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[loopover-orb]

Important

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