v0.1.0

Diagnose an unreachable Ollama by error type, not by error text

CI disagreed with a laptop about what a refused connection to port 1
says, so the diagnosis fell through to "Could not reach Ollama at …" —
a sentence that tells a reader nothing the screen had not already told
them, and two tests said so.

Matching on the operating system's wording was the mistake. The causes
are recognised by type now: ECONNREFUSED, net.DNSError, and the deadline
errors. The fallback carries the underlying error and still names the
first thing to try, because if AgentMux cannot reach Ollama then "start
Ollama" is worth saying however the failure was worded.

The branches are pinned against synthetic errors, so no machine's phrasing
can decide whether they pass. The two tests that go through a real socket
now assert only that the answer is useful.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014GpqNMx6Usfeoq7vB9HQxT