perf(version): cache parsed version tuples in compareVersions

[luojiyin1987]

Closes #739

Summary

compareVersions is on the hot path: candidate sorting, range matching, and fix validation all call it repeatedly. Each call splits strings and maps them to numbers. For a packument like lodash with 100+ versions, sorting calls compareVersions ~700 times, re-parsing the same strings each time.

Changes

• Added a Map<string, readonly (number|string)[]> cache in src/utils/version.ts
• Extracted parsing into parseVersionTuple that checks the cache before splitting
• Used Object.freeze to prevent mutation of cached arrays
• Return type is readonly for TypeScript-level enforcement

Verification

• TypeScript: no errors
• 46/46 tests pass

[sonukapoor]

The implementation is clean - Object.freeze on cached arrays is a nice touch. Two small things before this is good to go.

[sonukapoor]

Branch is one commit behind main after #742 merged. Could you rebase when you get a chance? No conflicts expected — the files don't overlap.

[sonukapoor]

Merged — thank you @luojiyin1987!

[luojiyin1987]

Branch is one commit behind main after #742 merged. Could you rebase when you get a chance? No conflicts expected — the files don't overlap.

something I need to do ?