Add Web Interface section covering:
- How to build the server binary (make build-server / make build-all)
- How to run it with the --addr flag
- What the web UI does and all API endpoints (POST /api/traverse,
GET /api/traverse/{id}, SSE stream, GET /api/health)
- Request/response shapes and SSE event format
Also update Makefile with build-server and build-all targets, and
expand Project Structure and Development sections to include the
new cmd/server/ and web/api/ packages.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>
