Document llmwiki-serve 0.2.0 source surfaces

[HwangJohn]

Summary

• Document the llmwiki-serve 0.2.0 source contract now merged to serve main.
• Update API/CLI/quickstart/status/architecture/troubleshooting docs for rich /health discovery, /graph/neighborhood, MCP llmwiki_graph_neighbors, and --producer-manifest freshness markers.
• Keep Redis/projection-store docs out of this PR because that serve work is not merged to main.

Validation

• npm run check
• git diff --check
• Changed-file sensitive-data scan: no private endpoint, local path, or secret patterns.

Notes

This is a docs-only companion to llmwiki-serve PR #11. It does not change package code or generated public assets beyond the VitePress build check.