perf: cache validateApiKey and proxyPool lookups, replace uuid with native randomUUID

[mahdiwafy]

Summary

Optimize middleware and repository hot paths to reduce per-request latency:

Changes

1. src/dashboardGuard.js - Reduce auth logging noise in hot path

   • Successful API key validation logs now behind DEBUG_AUTH env
   • Failed/invalid key logs remain visible
   • Trusted host (PUBLIC_API_HOSTS) logic extracted and clarified

2. src/lib/db/repos/apiKeysRepo.js - Add 2s in-memory validation cache

   • validateApiKey() now caches hits for 2 seconds
   • Cache auto-invalidated on create/update/delete API key
   • Cache TTL respects key expiresAt if sooner
   • Benchmark: first DB hit ~60ms, 1000 cached calls ~0.57ms total

3. src/lib/db/repos/proxyPoolsRepo.js - Add 2s in-memory proxy pool cache

   • getProxyPools() and getProxyPoolById() cached for 2 seconds
   • Cache auto-invalidated on create/update/delete proxy pool
   • Critical for noAuth free provider path (opencode, etc.)
   • Benchmark: first list hit ~70ms, 1000 cached calls ~1ms total

4. src/lib/db/repos/connectionsRepo.js - Replace uuid dependency

   • Use native crypto.randomUUID() instead of uuid package
   • Eliminates startup warning: "Cannot find package 'uuid' imported from connectionsRepo.js"

Verification

• npm run lint:undef — clean
• npm run build — exit 0
• Docker build — success (vansrouter:optimized-auth-proxy-cache)
• Deployed container vansrouter on port 20128 — healthy
• Warm /v1/models with API key: avg 0.0075s (cached)
• /v1/chat/completions via OPENCODE: HTTP 200 in ~3.2s
• Startup logs clean — no uuid warning, no auth spam