mcp: credentials leave the tree, and sub-agents lose the task board ...

Five tracked configs (gnexus-creds, gntodo, hard-panel, synapse, tgclient)
carried live bearer tokens — in git, in every clone, and handed to the admin
client by GET /admin/mcp/config. They now name a variable, and the value lives
in the service .env (chmod 600, untracked).

Substitution happens once, at transport open, next to the project-relative
path resolution: that is the single place a transport is built, so every
stored and serialised config stays placeholder-only and save_mcp_servers —
reached by create_mcp_server and PUT /admin/mcp/config — cannot write a secret
back into a tracked file. A variable that is not set refuses the connection
instead of dropping the header, which would fail open: a server may answer an
unauthenticated request as an anonymous user rather than returning 401.

Sub-agents also drop gntodo, gnexus-creds, tgclient and synapse from their
scopes, and the runner injects a scope anchor unconditionally — a sub-agent
asked to echo one word had picked a project off the task board and researched
it for forty iterations.

Docs: docs/mcp.md#secrets, a migration recipe in deploy/UPDATE.md, the variable
names in .env.example and deploy/env.template, and a regression guard over the
tracked configs.

The old values stay in git history; rotating all five at their sources is the
remediation, not a follow-up.

mcp: dedicated runner task per client (fix cross-task cancel-scope on shutdown) ...

MCP client SDK transports (stdio/sse/streamable_http) + ClientSession are
anyio task groups whose cancel scopes require __aenter__/__aexit__ in the
SAME asyncio task. McpClient entered the transport in one task (lifespan
connect / health-check reconnect / request retry) and exited it in another
(lifespan teardown) -> RuntimeError: Attempted to exit cancel scope in a
different task than it was entered in.

Refactor McpClient to own a single long-running runner task that holds the
AsyncExitStack and performs ALL transport enter/exit + list_tools/call_tool.
The public async API (connect/disconnect/list_tools/call_tool/mark_disconnected)
just enqueues a _Cmd and awaits a Future, so callers from any task no longer
cross cancel-scope boundaries. connected/instructions mirror from the runner
onto the instance to stay sync-readable. disconnect() enqueues a stop command
and awaits shield(runner) so teardown isn't interrupted by lifespan cancel.

Also call mcp_manager.stop_health_check() BEFORE disconnect_all() in
AppContainer.shutdown() so the health-check task cannot enqueue onto a
client whose runner is being torn down. mark_disconnected() is now async
(queued) and its manager caller updated.

Regression test: connect in one task, list_tools in a second, disconnect in
a third — the exact scenario that raised the RuntimeError before.

Add MCP server support and fix memory tools user isolation ...

MCP integration:
- New navi/mcp/ package: client, manager, config, tools
- ToolRegistry learns register_external() for MCP tools
- reload_tools reconnects MCP servers on hot reload
- New built-in mcp_status tool
- Startup/shutdown wiring for MCP connections
- 12 new tests (unit + integration with real stdio server)

Memory tools fix:
- memory, memory_save, memory_search, memory_forget now read
  current_user_id from tool context and pass it to MemoryStore
- Fixes invisible facts for authenticated users

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>