perf: optimize file extension discovery in technology detection

[yacosta738]

💡 What: Optimized RepoMetadata::collect in src/skills/detect.rs to avoid redundant string allocations and map insertions for file extensions.
🎯 Why: The original code performed string formatting and map lookups for every file encountered during the directory walk, even for common extensions already processed.
📊 Impact: Reduces heap allocations from O(N) to O(M) where N is the number of files and M is the number of unique extensions. This significantly improves performance in large projects with thousands of files.
🔬 Measurement: Verified with cargo test skills::detect and confirmed logic avoids redundant work.

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PR created automatically by Jules for task 10111704374037346123 started by @yacosta738

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[coderabbitai]

📝 Walkthrough

Walkthrough

RepoMetadata::collect optimizes file extension recording during directory traversal by checking whether an extension already exists in the map before performing formatting and insertion operations. When present, formatting and insertion work are skipped entirely; when absent, both the dotted and non-dotted extension forms are inserted in a single conditional block.

Changes

Extension Collection Performance

Layer / File(s)	Summary
Extension map efficiency check src/skills/detect.rs	RepoMetadata::collect avoids constructing dot_ext and calling or_insert when the extension key is already present; both extension forms are inserted together in one conditional block when needed.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Poem

🐰 A rabbit hops through files with glee,
Finding extensions it can quickly see—
No extra work when already known,
One check replaces duplicates shown!
Efficiency blooms in the code we sow. 🌿

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description is directly related to the changeset, explaining the optimization of RepoMetadata::collect to avoid redundant string allocations and map insertions for file extensions.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title 'perf: optimize file extension discovery in technology detection' directly and clearly summarizes the main change—optimizing how file extensions are discovered in the technology detection module.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch perf-optimize-extension-discovery-10111704374037346123

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[sentry]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud