feat(profiles): phase 2 — atomic switch coordinator (#824)

* feat(profiles): ProfileSwitchCoordinator — atomic re-home on profile switch (phase 2)

* fix(ws): deterministic reconnect backoff in tests (testAutoReconnect flake)

* test(ws): harden testAutoReconnect against CI latency (stub token refresh, generous latches)

* test(profiles): remove static Dispatchers mock from coordinator test — it bled into HermesWsClientTest in full-suite runs

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/data/session/ProfileSwitchCoordinator.kt

@@ -0,0 +1,50 @@
+package com.m57.hermescontrol.data.session
+
+import com.m57.hermescontrol.data.local.AuthManager
+import com.m57.hermescontrol.data.model.SetActiveProfileRequest
+import com.m57.hermescontrol.data.remote.ApiClient
+import com.m57.hermescontrol.data.remote.NetworkResult
+import com.m57.hermescontrol.data.remote.safeApiCall
+import com.m57.hermescontrol.data.ws.HermesWsClient
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
+import kotlinx.coroutines.withContext
+
+/**
+ * The single flow that performs a profile switch — the mobile equivalent of
+ * desktop's re-home (``requestFreshSession`` + socket swap). Every surface
+ * that switches profiles goes through here, so the switch is atomic instead
+ * of a pile of scattered patches.
+ *
+ * Order matters:
+ *  1. Flip the server's sticky active profile (REST).
+ *  2. Persist the LOCAL selection — the REST interceptor (``?profile=``) and
+ *     the WS params injector (``params.profile``) now scope everything to the
+ *     new profile. The per-server token fallback (phase 1) keeps auth intact:
+ *     no re-login, restart-safe.
+ *  3. Emit [switched] BEFORE the socket re-dial, so chat wipes its stale
+ *     conversation first — when the reconnected socket delivers
+ *     ``gateway.ready``, ``handleGatewayReady`` sees no open session and
+ *     auto-creates a FRESH session in the new profile (desktop parity).
+ *  4. Re-dial the WebSocket so the gateway re-homes chat to the new profile.
+ */
+object ProfileSwitchCoordinator {
+    private val _switched = MutableSharedFlow<String>(extraBufferCapacity = 1)
+    val switched: SharedFlow<String> = _switched.asSharedFlow()
+
+    suspend fun switchProfile(name: String): NetworkResult<Unit> {
+        val result =
+            withContext(Dispatchers.IO) {
+                safeApiCall { ApiClient.hermesApi.setActiveProfile(SetActiveProfileRequest(name)) }
+            }
+        if (result !is NetworkResult.Success) return result
+
+        AuthManager.setSelectedProfileId(name)
+        _switched.emit(name)
+        HermesWsClient.disconnect()
+        HermesWsClient.connect()
+        return result
+    }
+}