fix(signals): require a code file before manifest_missing_tests fires

[JSONbored]

Summary

• manifest_missing_tests fired on any PR with configured test expectations and no changed test file, even when the PR touched no code at all. Real production evidence: on JSONbored/awesome-claude, this check blocked 18 PRs and 9 merged anyway (50% false-positive rate), overwhelmingly single-file .mdx/README.md catalog-registration PRs with nothing a test could cover.
• The sibling local_diff_missing_tests check already guards on codeFileCount > 0; this PR ports the same guard to both buildFocusManifestGuidance implementations (src/signals/focus-manifest.ts and the packages/loopover-engine copy) so they stay in sync.

Scope

• The PR title follows type(scope): short summary Conventional Commit format.
• 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.
• Linked issue — N/A. Maintainer-authored fix found via a production ops-anomaly detector, not a contributor PR.

Validation

• git diff --check
• npm run actionlint
• npm run typecheck
• npm run test:coverage locally — 851 passed, 0 failed (full unsharded run). Both branches of the new codeFileCount > 0 guard are exercised: fires when a code file exists, does not fire on a docs/content-only change, still fires on a mixed code+docs change.
• npm run test:workers — not run, see note below
• npm run build:mcp / npm run test:mcp-pack — not run, see note below
• npm run ui:openapi:check / ui:lint / ui:typecheck / ui:build — not run, see note below
• npm audit --audit-level=moderate — clean, 0 vulnerabilities
• New/changed behavior has unit/integration tests for both branches of the new condition, plus a regression test for the reported false-positive

If any required check was skipped, explain why:

• test:workers, build:mcp/test:mcp-pack, and the ui:* checks were not run. This change is confined to src/signals/focus-manifest.ts, packages/loopover-engine/src/focus-manifest/guidance.ts, and their unit tests — no Workers runtime, MCP package, API route, OpenAPI schema, or UI code is touched. Ran npm run test:coverage (unsharded) and npm run test:engine-parity instead, which exercise this exact code path end-to-end and confirmed no golden-fixture drift.

Safety

• No secrets, wallets, hotkeys, coldkeys, trust scores, or reward values touched.
• Public GitHub finding text (title/detail/action strings) is unchanged in content — only the trigger condition changed.
• Auth/CORS/GitHub App/Cloudflare/session, API/OpenAPI/MCP, UI, and docs/changelog: not applicable, none touched.

UI Evidence

N/A — no UI/frontend/docs change.

Notes

• A pre-existing test (test/unit/queue-2.test.ts) was incidentally relying on this exact bug: its fixture used a README.md-only changed file to test an unrelated "an ignored-bot author still gets the deterministic gate" behavior. Fixed the fixture to use a code file so it continues to test its actual subject instead of silently depending on the false positive.

[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 95.11%. Comparing base (db74aa3) to head (c120a2c).
⚠️ Report is 4 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5852   +/-   ##
=======================================
  Coverage   95.11%   95.11%           
=======================================
  Files         586      586           
  Lines       46480    46482    +2     
  Branches    14860    14860           
=======================================
+ Hits        44209    44211    +2     
  Misses       1515     1515           
  Partials      756      756           

Flag	Coverage Δ
shard-1	43.73% <100.00%> (+<0.01%)	⬆️
shard-2	36.23% <75.00%> (+<0.01%)	⬆️
shard-3	32.15% <50.00%> (+0.06%)	⬆️
shard-4	32.90% <25.00%> (+0.07%)	⬆️
shard-5	31.64% <100.00%> (+<0.01%)	⬆️
shard-6	44.50% <50.00%> (-0.04%)	⬇️

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

Files with missing lines	Coverage Δ
...ges/loopover-engine/src/focus-manifest/guidance.ts	100.00% <100.00%> (ø)
src/signals/focus-manifest.ts	99.65% <100.00%> (+<0.01%)	⬆️

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