Add an optional project_path to every MCP tool so one server process can
answer against many projects. Omitted -> the server's default graph (fully
backward-compatible); an absolute project_path -> that project's
<GRAPHIFY_OUT>/graph.json, routed per call.
Implementation (all in _build_server):
- _ctx_cache + _load_ctx(): per-graph context cache with mtime+size
hot-reload, unified across the default graph and every project graph.
Unlike _load_graph it raises instead of sys.exit on a bad file.
- _resolve_graph_path()/_select_graph(): map project_path to a graph.json
and rebind G/communities/active_graph_path per call. No hot-path lock:
select+handler run in one synchronous span of the call_tool coroutine.
- Tolerant startup: serve with no default graph (pure multi-project mode)
instead of exiting; a bad project_path is a tool error, not a crash.
- project_path injected as an optional (non-required) field on all tools.
Tests: 3 new HTTP-transport tests (optional-on-every-tool, routing,
bad-path-no-crash). Full serve suite green (91 passed).
Joan F Garcia
9e7fbcbd6e