Merge fix/session-switch-reconnect: tear down + reconnect on session switch

Sources/UI/Terminal/MainTerminalView.swift

@@ -48,8 +48,22 @@ struct MainTerminalView: View {
             .padding(.vertical, 4)
             .background(Color(uiColor: .secondarySystemBackground))
         }
-        .task { await bootstrap() }
+        .task { await initialBootstrap() }
         .task { await registry.refresh(credential: credential) }    // T-2.6
+        .onChange(of: activeSessionId) { _, newId in
+            guard let newId else { return }
+            // Avoid reconnect storm if id already matches the current connection.
+            if connection?.id == newId { return }
+            Task {
+                if let oldConn = connection { await oldConn.suspend() }
+                cancellables.removeAll()
+                connection = nil
+                currentPiState = nil
+                sessionName = ""
+                terminalVC.feed(data: Data("\u{1B}[H\u{1B}[2J".utf8))
+                await bootstrap(sessionId: newId)
+            }
+        }
         .sheet(isPresented: $showSwitcher) {                        // T-2.6
             SessionSwitcher(registry: registry, credential: credential) { session in
                 activeSessionId = session.id
@@ -63,10 +77,21 @@ struct MainTerminalView: View {
 
     // MARK: - Bootstrap
 
-    private func bootstrap() async {
+    private func initialBootstrap() async {
         statusText = "Looking for sessions…"
         do {
             let sessionId = try await resolveSession()
+            await bootstrap(sessionId: sessionId)
+        } catch {
+            statusText = "Error: \(error.localizedDescription)"
+        }
+    }
+
+    private func bootstrap(sessionId: String) async {
+        // Keep activeSessionId in sync. The .onChange handler guards against
+        // re-entry via `connection?.id == newId` check (connection is still nil here
+        // on first call, but we set it below before any further state change).
+        activeSessionId = sessionId
         statusText = "Connecting to \(sessionId)…"
         let conn = SessionConnection(id: sessionId, credential: credential)
 
@@ -161,9 +186,6 @@ struct MainTerminalView: View {
                 ? ResumeCursor().lastSeq(for: sessionId)
                 : nil
             await conn.resume(from: lastSeq)
-        } catch {
-            statusText = "Error: \(error.localizedDescription)"
-        }
     }
 
     // MARK: - Session resolution