⚡ Bolt: [performance improvement]

[raccioly]

💡 What: Implemented a memoization cache (filterCache) within cli/shared-ignore.mjs for the buildIgnoreFilter function. It uses the stringified patterns array as a cache key to avoid redundant regular expression compilation.

🎯 Why: During directory traversal, validators repeatedly construct ignore filters with identical config arrays. Calling globToRegex and mapping the patterns into RegExp objects inside tight recursive loops caused an O(N*M) performance bottleneck, as seen in the benchmarking script (perf-test-shared-ignore.mjs) taking ~784ms for 100k iterations.

📊 Impact: The execution time of identical ignore filter setups was reduced by roughly ~88% in micro-benchmarks (down from ~784ms to ~94ms for 100k invocations). This provides a measurable speedup during deep recursive scans across the entire CLI validation lifecycle.

🔬 Measurement: The improvement was verified via a custom Node.js timing script that simulated repetitive shouldIgnore calls and by running the full test suite (pnpm test), ensuring zero functional regressions for ignored files.

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PR created automatically by Jules for task 10162582963630816006 started by @raccioly

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