fix(review): skip bytecode paths in grounding and diff priority

[jimcody1995]

Summary

• Extend SKIP_EXT in review-grounding.ts so fetchFullFileContents skips Java bytecode (.class, .jar) and Python bytecode (.pyc, .pyo).
• Align diffFilePriority in review-grounding.ts and review-diff.ts so those paths rank as noise(4) under a tight diff budget — same tier as lockfiles/minified/source maps.
• Unit tests record getFileContent calls and assert bytecode paths are never requested, plus direct diffFilePriority assertions for all four extensions.

Fixes #561

Scope

• Conventional Commit title format.
• Focused — review grounding/diff + unit tests only.
• Follows CONTRIBUTING.md.
• Linked issue for traceability (incremental slop/review-signal hygiene under the feat(signals): slop signal — generated/vendored/dependency/docs matchers #561 epic).

Validation

• git diff --check
• npm run test:ci on Node 22
• npm audit --audit-level=moderate — 0 vulnerabilities
• Unit tests cover SKIP_EXT fetch skip + diffFilePriority noise ranking

Safety

• No secrets, auth, or UI changes.
• N/A for UI Evidence.

UI Evidence

N/A — backend review grounding only.

Notes

Conflict avoidance: Touches only src/review/review-grounding.ts, src/review/review-diff.ts, and their unit tests. Zero overlap with open PRs (#3580 path-matchers Java gRPC, #3585 enrichment binary-extensions, #3586 hardcoded-URL, #3584/#3582 unused-export, #3577 suggested-change blocks, #3550 manual-review label).

Supersedes closed #3588 (same change; added linked issue + diffFilePriority parity per bot review).

Made with Cursor

[superagent-security]

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

[JSONbored]

Please work on new/open issues, not closed issues.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.19%. Comparing base (b98229d) to head (366c86e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3592   +/-   ##
=======================================
  Coverage   93.19%   93.19%           
=======================================
  Files         313      313           
  Lines       31874    31874           
  Branches    11666    11666           
=======================================
  Hits        29705    29705           
  Misses       1517     1517           
  Partials      652      652           

Files with missing lines	Coverage Δ
src/review/review-diff.ts	90.90% <100.00%> (ø)
src/review/review-grounding.ts	92.85% <100.00%> (ø)

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