fix(review): retry a 503 REES startup ping before escalating (#5006)

[JSONbored]

Summary

• Fixes fix(rees): investigate a REES /v1/ping 503 (7 Sentry events) #5006: REES's /v1/ping startup probe returned an unexpected 503 (GITTENSORY-1J, 7 events, all in a single ~5 hour window on 2026-07-08/09, never recurring since).
• Root cause: REES's server.ts /v1/ping handler returns 503 with exactly one meaning — if (!secret) return c.json({ error: "service_not_configured" }, 503); — i.e. REES's own REES_SHARED_SECRET isn't populated yet on that side. The engine's startup probe (probeReesSecretAtStartup, src/review/enrichment-wire.ts) already has an explicit, documented tolerance for the sibling benign startup race — a refused connection ("REES may not be up yet at engine start", logged at warn, never Sentry-visible) — but treated a 503 identically to a genuine unexpected error, escalating to console.error (Sentry-visible) on the very first response with zero tolerance.
• Requirement chore(release): prepare public gittensory launch #2 (correlate with other REES issues in this batch): checked — GITTENSORY-15's window (2026-07-02–07-05) and this one (2026-07-08–07-09) don't overlap, so this isn't the same deploy/restart window as another issue in this batch. It's its own event, standing on its own evidence (7 events in one clustered window, zero since) — consistent with a one-time deploy/restart timing race on the self-host operator's side, not a persistent misconfiguration.
• Fix: retry a 503 specifically (any other status is still final immediately) up to twice, 500ms apart, before escalating — mirroring the same "retry the ambiguous-but-likely-transient case before treating it as a real problem" pattern used throughout this session's other fixes (fix(review): ci_stuck_review_repeat_suppressed logs itself as an error on every suppression (650 Sentry events) #4998, fix(orb): /v1/orb/token still returns 500 after the #orb-broker-500 fix (95 Sentry events) #5000, fix(github): unhandled transient GitHub states in merge/assignee retries (3 Sentry events) #5003). A persistent 503 (e.g. a genuine, ongoing misconfiguration) still correctly escalates after the retries exhaust.

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 #5006).

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
• 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/unit/enrichment-wire.test.ts (51 tests) and confirmed via lcov that every changed line and both branches of the new retry loop are covered.
• actionlint / test:workers / build:mcp / test:mcp-pack / ui:openapi:check / ui:lint / ui:typecheck / ui:build / npm audit: not run — this change touches only src/review/enrichment-wire.ts (existing fire-and-forget startup probe, no new API/schema/binding/dependency surface) and its tests; no workflow, MCP, UI, or dependency-manifest 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. (N/A — this is a startup diagnostic probe, not an auth surface; a persistent-503 negative test and a genuine-401/403-mismatch test are both preserved/unaffected.)
• API/OpenAPI/MCP behavior is updated and tested where needed. (N/A.)
• 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 #13 and the last by priority.

[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 94.29%. Comparing base (34437c9) to head (942b74f).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5043   +/-   ##
=======================================
  Coverage   94.28%   94.29%           
=======================================
  Files         462      462           
  Lines       39367    39376    +9     
  Branches    14363    14364    +1     
=======================================
+ Hits        37119    37128    +9     
  Misses       1593     1593           
  Partials      655      655           

Flag	Coverage Δ
shard-1	46.66% <20.00%> (-0.03%)	⬇️
shard-2	33.25% <20.00%> (-0.12%)	⬇️
shard-3	31.27% <20.00%> (-0.19%)	⬇️
shard-4	32.52% <20.00%> (-0.27%)	⬇️
shard-5	34.42% <100.00%> (+0.95%)	⬆️
shard-6	45.28% <20.00%> (+0.21%)	⬆️

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

Files with missing lines	Coverage Δ
src/review/enrichment-wire.ts	98.35% <100.00%> (+0.08%)	⬆️

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