Settings → MCP gains a Tools block for admins only: one button, then the
same report the tool prints — what loaded, how many are in the registry,
per-file errors, and names in enabled.json nothing answers to.

It sits inside the existing MCP tab rather than a new one: the reload
rewrites the toolset of the whole server, not just this user's MCP keys,
and it belongs next to the thing it affects. Non-admins never see it.

dist rebuilt together with the source, as the server serves the bundle.

The tab was empty on every install: it listed only servers whose config
declares a `user_key` slot, and no config declared one — which read as
"no MCP servers connected" even though five are wired to profiles.

- GET /mcp-keys now returns every server referenced by at least one
  profile, keyed ones first, with `accepts_user_key`, the slot location
  (null when there is none) and the profile ids that connect it. The
  per-user key store is skipped entirely when nothing has a slot.
- gnexus-creds declares `user_key: {header: Authorization, prefix:
  "Bearer "}` — it is the one server carrying a shared credential, so its
  personal-key field is now real: users with a key run under their own,
  users without one fall back to the shared default.
- The panel lists all servers (transport + profiles), dims the keyless
  rows, and shows a key input only for slotted ones, spelling out the
  shared-key fallback.

docs/api.md and docs/mcp.md updated; backend 1367 passed, webclient 148.