feat: T-2.6 SessionRegistry + SessionSwitcher UI

Sources/Core/Sessions/SessionRegistry.swift

@@ -0,0 +1,120 @@
+// Sources/Core/Sessions/SessionRegistry.swift
+// T-2.6: Session listing, creation, and deletion via the sidecar REST API.
+
+import Foundation
+
+// MARK: - SessionInfo
+
+public struct SessionInfo: Identifiable, Hashable, Sendable {
+    public let id: String
+    public let name: String
+    public let state: String  // "running", "idle", etc.
+}
+
+// MARK: - SessionRegistry
+
+@MainActor
+public final class SessionRegistry: ObservableObject {
+    @Published public var sessions: [SessionInfo] = []
+    @Published public var isLoading = false
+    @Published public var error: String? = nil
+
+    public init() {}
+
+    // MARK: - Private helpers
+
+    private func baseURL(credential: SidecarCredential) -> URL {
+        URL(string: "http://\(credential.host):\(credential.port)")!
+    }
+
+    private func authorizedRequest(url: URL, credential: SidecarCredential) -> URLRequest {
+        var req = URLRequest(url: url)
+        req.setValue("Bearer \(credential.bearerToken)", forHTTPHeaderField: "Authorization")
+        return req
+    }
+
+    // MARK: - GET /sessions
+
+    /// Fetches the current session list from the sidecar and updates `sessions`.
+    public func refresh(credential: SidecarCredential) async {
+        isLoading = true
+        error = nil
+        defer { isLoading = false }
+
+        let url = baseURL(credential: credential).appendingPathComponent("sessions")
+        let req = authorizedRequest(url: url, credential: credential)
+
+        do {
+            let (data, _) = try await URLSession.shared.data(for: req)
+            let items = try JSONDecoder().decode([SessionItem].self, from: data)
+            sessions = items.map { SessionInfo(id: $0.id, name: $0.name, state: $0.state) }
+        } catch {
+            self.error = error.localizedDescription
+        }
+    }
+
+    // MARK: - POST /sessions
+
+    /// Creates a new session with the given name and returns the created `SessionInfo`.
+    @discardableResult
+    public func spawnSession(name: String, credential: SidecarCredential) async throws -> SessionInfo {
+        let url = baseURL(credential: credential).appendingPathComponent("sessions")
+        var req = authorizedRequest(url: url, credential: credential)
+        req.httpMethod = "POST"
+        req.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        req.httpBody = try JSONEncoder().encode(["name": name])
+
+        let (data, response) = try await URLSession.shared.data(for: req)
+
+        guard let http = response as? HTTPURLResponse, (200..<300).contains(http.statusCode) else {
+            throw SessionRegistryError.unexpectedStatus
+        }
+
+        let item = try JSONDecoder().decode(SessionItem.self, from: data)
+        let info = SessionInfo(id: item.id, name: item.name, state: item.state)
+
+        // Append optimistically; a follow-up refresh will normalise order.
+        sessions.append(info)
+        return info
+    }
+
+    // MARK: - DELETE /sessions/<id>
+
+    /// Deletes the session with the given id.
+    public func deleteSession(id: String, credential: SidecarCredential) async throws {
+        let url = baseURL(credential: credential)
+            .appendingPathComponent("sessions")
+            .appendingPathComponent(id)
+        var req = authorizedRequest(url: url, credential: credential)
+        req.httpMethod = "DELETE"
+
+        let (_, response) = try await URLSession.shared.data(for: req)
+
+        guard let http = response as? HTTPURLResponse, (200..<300).contains(http.statusCode) else {
+            throw SessionRegistryError.unexpectedStatus
+        }
+
+        sessions.removeAll { $0.id == id }
+    }
+}
+
+// MARK: - Private Codable helper
+
+private struct SessionItem: Decodable {
+    let id: String
+    let name: String
+    let state: String
+}
+
+// MARK: - Errors
+
+public enum SessionRegistryError: LocalizedError {
+    case unexpectedStatus
+
+    public var errorDescription: String? {
+        switch self {
+        case .unexpectedStatus:
+            return "Unexpected HTTP status from sidecar."
+        }
+    }
+}

Sources/UI/Sessions/SessionRow.swift

@@ -0,0 +1,40 @@
+// Sources/UI/Sessions/SessionRow.swift
+// T-2.6: Row view for a single session in the SessionSwitcher list.
+
+import SwiftUI
+
+struct SessionRow: View {
+    let session: SessionInfo
+
+    var body: some View {
+        HStack {
+            Text(session.name)
+                .font(.body)
+            Spacer()
+            stateBadge
+        }
+    }
+
+    @ViewBuilder
+    private var stateBadge: some View {
+        HStack(spacing: 4) {
+            Circle()
+                .fill(badgeColor)
+                .frame(width: 8, height: 8)
+            Text(session.state)
+                .font(.caption)
+                .foregroundStyle(badgeColor)
+        }
+    }
+
+    private var badgeColor: Color {
+        switch session.state.lowercased() {
+        case "running", "active":
+            return .green
+        case "idle":
+            return .yellow
+        default:
+            return .secondary
+        }
+    }
+}

Sources/UI/Sessions/SessionSwitcher.swift

@@ -0,0 +1,92 @@
+// Sources/UI/Sessions/SessionSwitcher.swift
+// T-2.6: Sheet UI for listing, selecting, and creating sessions.
+
+import SwiftUI
+
+struct SessionSwitcher: View {
+    @ObservedObject var registry: SessionRegistry
+    let credential: SidecarCredential
+    let onSelect: (SessionInfo) -> Void
+
+    @Environment(\.dismiss) private var dismiss
+
+    @State private var showNewSessionAlert = false
+    @State private var newSessionName = ""
+    @State private var spawnError: String? = nil
+
+    var body: some View {
+        NavigationStack {
+            Group {
+                if registry.isLoading {
+                    ProgressView("Loading sessions…")
+                        .frame(maxWidth: .infinity, maxHeight: .infinity)
+                } else {
+                    List(registry.sessions) { session in
+                        Button {
+                            onSelect(session)
+                            dismiss()
+                        } label: {
+                            SessionRow(session: session)
+                        }
+                        .foregroundStyle(.primary)
+                    }
+                    .overlay {
+                        if registry.sessions.isEmpty {
+                            ContentUnavailableView(
+                                "No Sessions",
+                                systemImage: "terminal",
+                                description: Text("Tap + to create a session.")
+                            )
+                        }
+                    }
+                }
+            }
+            .navigationTitle("Sessions")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .cancellationAction) {
+                    Button("Done") { dismiss() }
+                }
+                ToolbarItem(placement: .primaryAction) {
+                    Button {
+                        newSessionName = ""
+                        spawnError = nil
+                        showNewSessionAlert = true
+                    } label: {
+                        Image(systemName: "plus")
+                    }
+                }
+            }
+            .alert("New Session", isPresented: $showNewSessionAlert) {
+                TextField("Session name", text: $newSessionName)
+                    .autocorrectionDisabled()
+                Button("Create") {
+                    let name = newSessionName.trimmingCharacters(in: .whitespaces)
+                    guard !name.isEmpty else { return }
+                    Task {
+                        do {
+                            try await registry.spawnSession(name: name, credential: credential)
+                            await registry.refresh(credential: credential)
+                        } catch {
+                            spawnError = error.localizedDescription
+                        }
+                    }
+                }
+                Button("Cancel", role: .cancel) {}
+            } message: {
+                Text("Enter a name for the new session.")
+            }
+            .safeAreaInset(edge: .bottom) {
+                if let err = registry.error ?? spawnError {
+                    Text(err)
+                        .font(.caption)
+                        .foregroundStyle(.red)
+                        .padding(8)
+                        .frame(maxWidth: .infinity, alignment: .leading)
+                        .background(Color(uiColor: .secondarySystemBackground))
+                }
+            }
+        }
+        .task { await registry.refresh(credential: credential) }
+    }
+}

Sources/UI/Terminal/MainTerminalView.swift

@@ -14,6 +14,9 @@ struct MainTerminalView: View {
     @State private var statusText = "Connecting…"
     @State private var cancellables = Set<AnyCancellable>()
     @EnvironmentObject var appState: AppState
+    @StateObject private var registry = SessionRegistry()
+    @State private var showSwitcher = false
+    @State private var activeSessionId: String? = nil
 
     var body: some View {
         VStack(spacing: 0) {
@@ -23,6 +26,10 @@ struct MainTerminalView: View {
                     .font(.caption.monospaced())
                     .foregroundStyle(.secondary)
                 Spacer()
+                Button { showSwitcher = true } label: {
+                    Image(systemName: "list.bullet")
+                }
+                .font(.caption)
                 Button("Unpair") {
                     appState.unpair()
                 }
@@ -51,6 +58,17 @@ struct MainTerminalView: View {
             .background(Color(uiColor: .secondarySystemBackground))
         }
         .task { await bootstrap() }
+        .task { await registry.refresh(credential: credential) }
+        .sheet(isPresented: $showSwitcher) {
+            SessionSwitcher(
+                registry: registry,
+                credential: credential,
+                onSelect: { session in
+                    activeSessionId = session.id
+                    showSwitcher = false
+                }
+            )
+        }
     }
 
     // MARK: - Bootstrap