fix(client): say when the account's node is elsewhere, and let go of it

2026-10-10T07:57:29Z

Signing in on a desktop links this machine's node to the account, but never over a key already linked (that would cut off the user's other machine) nor a node set up for another account. On a real install both left the node reading "Running" while the hub refused it in a loop, and nothing said why. And the only way to unlink was the linked machine's own Node page, of no use once that machine is gone. - The Node page works out, from the node and the hub each time it looks, whether this node can serve the signed-in account (nodeLinkProblem), and says why not: "Link this node instead" (asked first) puts this node's key on the account; "Use this node for my account" switches a node set up for another account through node:start, which takeOver now lets past a node that answers "running". The first version went through node:start for both, and clicking it on a real install did nothing: a node signed in before the account was linked elsewhere answers "running". - The Profile page unlinks the account's node (DELETE /v1/users/me/node_key), from any machine. Co-Authored-By: Claude Opus 5.5

meshbay.git/packages/meshbay-hub/tests/test_node_link_banner.py, branch main

fix(client): say when the account's node is elsewhere, and let go of it