[spelech]

Summary

Fixes 7 issues discovered during Windows x64 portable bundle field testing:

1. Server Startup Hang (portable_postgres.py): pg_ctl start was executed with capture_output=True, which on Windows caused the inherited postgres child process pipe to block subprocess.run() indefinitely. Output is now redirected to data/pg_ctl.out with stdin=subprocess.DEVNULL and a 120s timeout.
2. PowerShell 5.1 Compatibility (scripts/portable/): start-contextcortex.bat invokes Windows PowerShell 5.1, which failed on the PowerShell 7 ?? null-coalescing operator. Extracted the launcher and .env.example into scripts/portable/ with PS 5.1 compatibility and CRLF line endings via .gitattributes.
3. CA Bundle Public Root Retention (start-contextcortex.ps1): Preserves _internal/certifi/cacert.pem public root CAs when appending corporate .crt/.pem certificates from .\certs\.
4. Frozen Exe Path Resolution (main.py): Sets DATA_DIR, VAULT_PATH, CACHE_DB_PATH, VECTOR_STORE_STORAGE_PATH, and TMP_REPOS_DIR next to contextcortex.exe before app.* imports when running frozen.
5. Default API Embedding Provider (main.py, .env.example): Defaults EMBEDDING_PROVIDER=api and EMBEDDING_MODEL=text-embedding-3-small in frozen mode so the first startup does not create a 384-dim local FastEmbed table.
6. Cold-Start Model Discovery Timeout (litellm_service.py): Increased /v1/models discovery timeout from 6.0s to 15.0s.
7. CI Runtime Smoke Test (build-portable-windows.yml): Starts contextcortex.exe in CI, bootstraps portable PostgreSQL + pgvector, and verifies /ready reports status == 'ready' and database.type == 'postgresql' before packaging the zip.