fix: Wave 4 - memory leaks, JSONC bug, timeout extension

- Fix TTLCache passive-purge + add maxSize with LRU eviction
- Bound NiaSessionState.cache (500) and projectContext (100) Maps
- Fix JSONC regex to not break URLs with //
- Deduplicate JSONC stripping logic in cli.ts
- Extend universal search timeout to 120s

Tests: 58 pass, 0 fail