chore(release): v0.2.6 — Settings UX, empty pool by default, CMF port check

- Settings: "?" help tooltips on every option; router key auto-probes the
  connection right after saving (no more hanging "unavailable")
- Local models card reworked into 3 clear steps (install cortiq → add model →
  run locally); removed the hand-entered .cmf path / pool-id fields — models
  are added via the Import tab and the managed server registers them
- Fresh install ships an EMPTY model pool; the local .cmf is auto-registered by
  the managed CMF server, so it needs no static [[models]] entry
- New: port-availability check — GET /admin/api/cmf/port + "Check port" button
  with next-free-port suggestion. bind()+connect() probe so Docker-proxied /
  dual-stack ports (e.g. 8081) are correctly detected as occupied
- /admin/api/cmf now reports the serving model + port; card shows "▶ serving …"
- On-demand runtime install: POST /admin/api/cmf/install

config/gateway.example.toml

@@ -142,7 +142,7 @@ max_entries = 1000
 manage_server = false                # true → gateway spawns `cortiq serve` at startup
 local_model   = "models/model.cmf"   # path to the .cmf to serve
 local_host    = "127.0.0.1"
-local_port    = 8081                  # must match the cmf-local base_url above
+local_port    = 8081                  # confirm it's free in Settings → "Check port" (8081 often clashes with Docker/Apache)
 model_id      = "cmf-local"           # id it registers under (matches [[models]])
 threads       = 8                     # decode worker threads (CMF_THREADS); ~3x vs serial
 gpu           = false                 # offload matvecs to GPU (Metal/wgpu); mainly a prefill win