PR #13: prefer streamable-http + fresher checks for reachable ranking

[khalidsaidi]

Summary

• add reachability tie-break helpers in apps/api/src/rag/search.ts:
  • remoteTypeWeight: streamable-http > sse > unknown
  • checkedAtMs: parse reachability check timestamps
• apply these tie-breakers only when filters.reachable === true
• keep relevance primary for /rag/search:
  • keyword/semantic score remains the first sort key
  • then apply reachability preferences
  • then existing quality signals (ragScore, updatedAt, name)
• update /rag/top ordering when reachable=true to prefer:
  • streamable-http over sse
  • more recently checked entries
  • then existing quality signals

Tests

Added deterministic integration tests in apps/api/tests/api.test.ts:

• rag top prefers reachable streamable-http over sse when reachable=true
• rag search prefers more recently checked entries when remote type ties

Validation

• pnpm -r test
• pnpm -r typecheck
• pnpm -r lint