Three commands turned a transport failure into something that reads as real
state:
- `keys add` aborted on any 4xx. `/api/v1/providers/keys` is not mounted on
the shipped server, so a 404 stranded the user with "HTTP 404" while the
SQLite fallback directly below it — which works — was unreachable whenever the
server was up. New isRouteUnavailableStatus() (404/405/501) lets the caller
fall through; genuine client errors (400/401/403/409/422/429) stay fatal.
- `providers test-all` reported every OAuth connection as FAILED because
getProviderApiKey() throws for non-apikey connections by design — and
persisted that verdict to provider_connections.test_status, marking healthy
OAuth providers broken. Those connections are now skipped. An "unsupported"
probe result (no recipe in PROVIDER_TEST_CONFIGS) is likewise a CLI gap, not
a provider failure, so it no longer overwrites a good test_status.
- `combo list` printed "No combos configured" when /api/combos returned
non-2xx, which is indistinguishable from genuine emptiness. It now reports the
status and exits non-zero.
Refs #10081
3ee5c1b4ae