fix: honor query-time provider config across search paths + skip no-op generation publish (smoke fixes)

[srobinson]

Summary

• Resolve one complete query provider configuration from CLI precedence, active namespace state, and persisted vector metadata for semantic CLI, hybrid CLI, and MCP search.
• Preserve stored vector availability when query embedding fails and expose the typed degradation reason in hybrid results.
• Compare staged and current logical indexes across structural and semantic artifacts, then discard validated staging for a full no-op refresh.
• Cover timestamp-only refresh, edit, deletion, semantic no-op, embedding-only changes, custom endpoints and models, and hybrid provider overrides.

Test plan

• npx --yes pnpm@10.28.0 test
• npx --yes pnpm@10.28.0 typecheck
• npx --yes pnpm@10.28.0 build
• npx --yes pnpm@10.28.0 check