feat: background tasks panel (Phase 7)

Sources/LiveKit/TaskStore.swift

@@ -0,0 +1,130 @@
+import Foundation
+import os
+
+private let logger = Logger(subsystem: "dev.shane.voice", category: "tasks")
+
+struct TaskStep: Identifiable, Equatable {
+    let id = UUID()
+    let role: String?
+    let content: String?
+}
+
+struct TaskItem: Identifiable, Equatable {
+    enum Status: Equatable {
+        case pending
+        case running
+        case completed
+        case failed
+    }
+
+    let id: String
+    var description: String
+    var status: Status
+    var steps: [TaskStep]
+    var result: String?
+    var error: String?
+    var createdAt: Date
+    var completedAt: Date?
+}
+
+/// Folds task_event messages into task items, mirroring the web UI's tasks Map.
+@MainActor
+final class TaskStore: ObservableObject {
+    @Published private(set) var tasks: [String: TaskItem] = [:]
+
+    var sortedTasks: [TaskItem] {
+        tasks.values.sorted { $0.createdAt > $1.createdAt }
+    }
+
+    var activeCount: Int {
+        tasks.values.filter { $0.status == .pending || $0.status == .running }.count
+    }
+
+    func apply(_ payload: ControlChannel.TaskEventPayload) {
+        guard let taskId = payload.taskId, !taskId.isEmpty else { return }
+        switch payload.type {
+        case "created":
+            tasks[taskId] = TaskItem(
+                id: taskId,
+                description: payload.description ?? "Background task",
+                status: .pending,
+                steps: [],
+                result: nil,
+                error: nil,
+                createdAt: date(from: payload.createdAt),
+                completedAt: nil
+            )
+        case "step":
+            var task = tasks[taskId] ?? TaskItem(
+                id: taskId,
+                description: payload.description ?? "Background task",
+                status: .pending,
+                steps: [],
+                result: nil,
+                error: nil,
+                createdAt: date(from: payload.createdAt),
+                completedAt: nil
+            )
+            task.steps.append(TaskStep(role: payload.role, content: payload.content))
+            if task.status == .pending { task.status = .running }
+            tasks[taskId] = task
+        case "completed":
+            var task = tasks[taskId] ?? TaskItem(
+                id: taskId,
+                description: payload.description ?? "Background task",
+                status: .pending,
+                steps: [],
+                result: nil,
+                error: nil,
+                createdAt: date(from: payload.createdAt),
+                completedAt: nil
+            )
+            task.status = .completed
+            task.result = payload.result
+            task.completedAt = Date()
+            tasks[taskId] = task
+        case "failed":
+            var task = tasks[taskId] ?? TaskItem(
+                id: taskId,
+                description: payload.description ?? "Background task",
+                status: .pending,
+                steps: [],
+                result: nil,
+                error: nil,
+                createdAt: date(from: payload.createdAt),
+                completedAt: nil
+            )
+            task.status = .failed
+            task.error = payload.error
+            task.completedAt = Date()
+            tasks[taskId] = task
+        default:
+            return
+        }
+        logger.log("task \(payload.type, privacy: .public) id=\(taskId, privacy: .public) steps=\(self.tasks[taskId]?.steps.count ?? 0, privacy: .public)")
+    }
+
+    func clear() {
+        tasks.removeAll()
+    }
+
+    #if DEBUG
+    func injectSampleEvents() {
+        let now = Date().timeIntervalSince1970
+        apply(ControlChannel.TaskEventPayload(type: "created", taskId: "sample-a", description: "Research the best coffee roasters in Portland", role: nil, content: nil, result: nil, error: nil, createdAt: now - 45))
+        apply(ControlChannel.TaskEventPayload(type: "step", taskId: "sample-a", description: nil, role: "thinking", content: "Searching for Portland roasteries…", result: nil, error: nil, createdAt: nil))
+        apply(ControlChannel.TaskEventPayload(type: "step", taskId: "sample-a", description: nil, role: "tool_result", content: "Found 12 results across 3 review sites.", result: nil, error: nil, createdAt: nil))
+        apply(ControlChannel.TaskEventPayload(type: "completed", taskId: "sample-a", description: nil, role: nil, content: nil, result: "Top three: Coava, Stumptown, and Heart Roasters — all scored 4.5+ across reviews.", error: nil, createdAt: nil))
+        apply(ControlChannel.TaskEventPayload(type: "created", taskId: "sample-b", description: "Compare iPhone 17 vs Pixel 10 battery life", role: nil, content: nil, result: nil, error: nil, createdAt: now - 20))
+        apply(ControlChannel.TaskEventPayload(type: "step", taskId: "sample-b", description: nil, role: "thinking", content: "Fetching benchmark articles…", result: nil, error: nil, createdAt: nil))
+        apply(ControlChannel.TaskEventPayload(type: "failed", taskId: "sample-b", description: nil, role: nil, content: nil, result: nil, error: "Search backend timed out after 30s", createdAt: nil))
+    }
+    #endif
+}
+
+private extension TaskStore {
+    func date(from interval: Double?) -> Date {
+        guard let interval, interval > 0 else { return Date() }
+        return Date(timeIntervalSince1970: interval)
+    }
+}