hotfix: doc-language penalty in rerankSignalScore (v0.2.5807)

[justrach]

Summary

Hotfix on top of v0.2.5807. Live-binary testing showed CHANGELOG.md and benchmark *.md files with 4-6 mentions of an identifier on one line outranking actual code call sites for queries like searchContent, handleCallers, pathHasSegment. The Tier 0 code-first ordering correctly retrieves source files, but the rerank's per-line frequency then re-promotes any markdown line with high mention density.

Same release tag v0.2.5807 — version not bumped per request. Assets will be re-uploaded with --clobber after merge.

Fix

In rerankSignalScore (src/explore.zig), cap doc-language scores at 1.0 then halve:

if (isDocLanguage(detectLanguage(r.path))) {
    score = @min(score, 1.0) * 0.5;
}

For doc files, more mentions don't reflect more code-relevance — they reflect prose density. Cap+halve ensures any code hit (score >= 1) outranks any markdown / json / yaml / unknown-language hit. Symmetric with the existing path-prior penalty for tests/, examples/, vendor/, node_modules/, third_party/.

Test

test "issue-429-e: searchContent rerank penalises doc-language files so code beats markdown noise" — a 4-mention markdown line vs a 1-mention code call site. Pre-fix the markdown line ranks #1; post-fix the code call site ranks #1.

zig build test exit 0 (461 tests).

Test plan

• zig build test
• Reviewer spot-check: src/explore.zig rerankSignalScore — confirm cap-and-halve uses @min not multiplication
• Re-run live binary on this repo: searchContent, handleCallers, pathHasSegment, BenchContext — markdown files should rank below code

🤖 Generated with Claude Code

[github-actions]

Benchmark Regression Report

Thresholds: 10.00% and 50,000 ns absolute delta

NOISE means the percentage threshold was exceeded, but the absolute delta was too small to fail CI.

Tool	Base (ns)	Head (ns)	Delta	Abs Delta (ns)	Status
codedb_bundle	535675	548449	+2.38%	+12774	OK
codedb_changes	53178	56284	+5.84%	+3106	OK
codedb_deps	10094	9742	-3.49%	-352	OK
codedb_edit	6141	6133	-0.13%	-8	OK
codedb_find	62896	61432	-2.33%	-1464	OK
codedb_hot	99796	98929	-0.87%	-867	OK
codedb_outline	302227	304358	+0.71%	+2131	OK
codedb_read	94098	97226	+3.32%	+3128	OK
codedb_search	198876	209369	+5.28%	+10493	OK
codedb_snapshot	281552	283168	+0.57%	+1616	OK
codedb_status	213253	215769	+1.18%	+2516	OK
codedb_symbol	61312	60642	-1.09%	-670	OK
codedb_tree	81939	80492	-1.77%	-1447	OK
codedb_word	70815	71297	+0.68%	+482	OK