fix(selfhost): stabilize REES validation and RAG coalescing

[JSONbored]

Summary

• Fixes fix(queue): coalesce scheduled RAG full re-index over pending webhook incrementals #1949.
• Stabilizes REES Sentry release validation by retrying the existing post-upload validation briefly so deploys do not fail while Sentry is still surfacing the associated commit and deploy metadata.
• Coalesces scheduled full RAG repo index jobs over pending webhook incrementals for the same repo, while preserving incrementals when no full job is pending.
• No separate GitHub issue for the REES deploy failure; this patches the observed GITTENSORY-X deploy blocker directly.

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 coverage of the lines and branches changed.
• 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:

• None. npm run test:ci passed and includes the checked CI commands above.

Safety

• No secrets, credentials, private keys, user PATs, 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 where applicable. This PR does not change those surfaces.
• API/OpenAPI/MCP behavior is updated and tested where needed. This PR does not change API, OpenAPI, or MCP behavior.
• UI changes use live API data or real empty/error/loading states, not production mock/demo fallbacks. This PR has no UI changes.
• Visible UI changes include a UI Evidence section below with JPG/JPEG or PNG screenshots arranged as organized, captioned, clickable thumbnails. This PR has no visible UI changes.
• Public docs/changelogs are updated where needed; changelogs are only edited for release-prep PRs. No docs or changelog update is needed.

UI Evidence

Not applicable; no visible UI, frontend, docs, or extension changes.

Notes

• npm run test:ci emits existing UI lint warnings about fast-refresh component exports; the command completed successfully.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.71%. Comparing base (704cebc) to head (e32ee1e).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2116   +/-   ##
=======================================
  Coverage   95.71%   95.71%           
=======================================
  Files         222      222           
  Lines       24620    24653   +33     
  Branches     8936     8945    +9     
=======================================
+ Hits        23565    23597   +32     
- Misses        432      433    +1     
  Partials      623      623           

Files with missing lines	Coverage Δ
src/selfhost/queue-common.ts	92.85% <100.00%> (+0.05%)	⬆️
src/selfhost/sqlite-queue.ts	99.24% <100.00%> (+0.05%)	⬆️

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