feat: Add pytest error extractor for Python test output

[jdutton]

Summary

• Adds a new pytest extractor plugin (priority 92) that parses Python pytest output into structured file:line:message errors for LLM consumption
• Fixes false-positive where the jasmine extractor matched pytest output at 90% confidence, reporting 0 errors despite exit code 1
• Adds .gitignore patterns for TypeScript compilation artifacts (*.d.ts, *.d.ts.map, *.js.map) that could leak outside dist/

Detection (3 confidence tiers)

• 95%: platform ... -- Python X.Y.Z, pytest-X.Y.Z header
• 90%: short test summary info + .py:: test paths
• 85%: pytest summary format (N passed, N failed) + .py paths

Extraction (3 parsing strategies)

• FAILURES section: Assertion errors with E prefixed lines and file.py:NN: locations
• ERRORS section: Collection/import errors with tracebacks (e.g., TypeError: unsupported operand type(s) for |)
• Short summary fallback: FAILED/ERROR lines when detailed sections absent

Verified against real-world output

Tested against lfa-cc-marketplace where 3 pytest collection errors (Python 3.9 vs 3.10+ str | None syntax) were previously invisible — now correctly extracted with file/line/message.

Test plan

• 12 tests built via TDD red-green-refactor (5 detection, 4 extraction, 1 metadata, 2 samples)
• pnpm validate passes (all phases green)
• Pre-commit hooks pass
• Verified against real lfa-cc-marketplace pytest output

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 98.45560% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.79%. Comparing base (97a0583) to head (917d7f8).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/extractors/src/extractors/pytest/index.ts	98.39%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #136      +/-   ##
==========================================
+ Coverage   85.57%   85.79%   +0.22%     
==========================================
  Files         114      115       +1     
  Lines       14809    15068     +259     
  Branches     3187     3245      +58     
==========================================
+ Hits        12673    12928     +255     
- Misses       2136     2140       +4     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud