feat(#101): Add Task Progress widget for orchestrator task monitoring

Create TaskProgressWidget showing live agent task execution progress:
- Fetches from orchestrator /agents API with 15s auto-refresh
- Shows stats (total/active/done/stopped), sorted task list
- Agent type badges (worker/reviewer/tester)
- Elapsed time tracking, error display
- Dark mode support, PDA-friendly language
- Registered in WidgetRegistry for dashboard use

Includes 7 unit tests covering all states.

Fixes #101

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/src/components/widgets/WidgetRegistry.tsx

@@ -9,6 +9,7 @@ import { CalendarWidget } from "./CalendarWidget";
 import { QuickCaptureWidget } from "./QuickCaptureWidget";
 import { AgentStatusWidget } from "./AgentStatusWidget";
 import { ActiveProjectsWidget } from "./ActiveProjectsWidget";
+import { TaskProgressWidget } from "./TaskProgressWidget";
 
 export interface WidgetDefinition {
   name: string;
@@ -83,6 +84,17 @@ export const widgetRegistry: Record<string, WidgetDefinition> = {
     minHeight: 2,
     maxWidth: 4,
   },
+  TaskProgressWidget: {
+    name: "TaskProgressWidget",
+    displayName: "Task Progress",
+    description: "Live progress of orchestrator agent tasks",
+    component: TaskProgressWidget,
+    defaultWidth: 2,
+    defaultHeight: 2,
+    minWidth: 1,
+    minHeight: 2,
+    maxWidth: 3,
+  },
 };
 
 /**