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

src/cmf_runtime.rs

@@ -119,7 +119,7 @@ async fn latest_crates_version() -> Option<String> {
 }
 
 /// `<bin> --version` → the trailing version token (e.g. "cortiq 0.1.2" → "0.1.2").
-fn installed_version(bin: &str) -> Option<String> {
+pub(crate) fn installed_version(bin: &str) -> Option<String> {
     let out = std::process::Command::new(bin).arg("--version").output().ok()?;
     if !out.status.success() {
         return None;
@@ -152,6 +152,21 @@ async fn cargo_install(force: bool) -> Result<(), String> {
     }
 }
 
+/// Install/upgrade `cortiq-cli` from crates.io on demand (the admin "Install
+/// cortiq" button). Runs in the background; progress + result land in the CMF
+/// status log, and `installed_version` is refreshed on success.
+pub async fn install_now(rt: Arc<CmfRuntime>, bin: String) {
+    rt.log("installing cortiq-cli from crates.io (this compiles — a few minutes)…");
+    match cargo_install(true).await {
+        Ok(()) => {
+            let v = installed_version(&bin);
+            rt.status.lock().unwrap().installed_version = v.clone();
+            rt.log(format!("installed cortiq-cli {}", v.as_deref().unwrap_or("?")));
+        }
+        Err(e) => rt.fail(format!("cargo install cortiq-cli failed: {e}")),
+    }
+}
+
 /// Spawn `cortiq serve <model> --host <host> --port <port>`; the child is killed
 /// when its handle is dropped (i.e. when the gateway shuts down).
 fn spawn_serve(cfg: &CmfCfg) -> Result<Child, String> {