Phase 2: Refactor Tasks cluster to MCP SDK types

Replace ad hoc TaskCardProps data shape with SDK Task type across the
Tasks group components and TasksScreen.

- TaskCard: accept `task: Task` instead of flat props (taskId, status,
  method, target, progress, etc.); derive all display fields from the
  SDK Task object (taskId, status, ttl, createdAt, lastUpdatedAt,
  statusMessage); remove fields not present on SDK Task (method, target,
  progress as number, error, completedAt, elapsed)
- TaskControls: type statusFilter as `TaskStatus | undefined`; add
  runtime validation guard on Select onChange
- TaskListPanel: accept `Task[]` instead of `TaskCardProps[]`; pass
  `onCancel(taskId)` through to each TaskCard; use `task.taskId` as key
- TasksScreen: accept `Task[]` + `onCancel(taskId)` callback; type
  internal statusFilter state as `TaskStatus | undefined`
- Delete re-export of `TaskStatus` from TaskCard (import directly from
  SDK where needed)
- Update all stories with real SDK `Task` fixtures
- Update ConnectedView TasksActive story

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

clients/web/src/components/groups/TaskControls/TaskControls.tsx

@@ -16,9 +16,9 @@ const ToolbarButton = Button.withProps({
 
 export interface TaskControlsProps {
   searchText: string;
-  statusFilter?: string;
+  statusFilter?: TaskStatus;
   onSearchChange: (text: string) => void;
-  onStatusFilterChange: (status: string) => void;
+  onStatusFilterChange: (status: TaskStatus | undefined) => void;
   onRefresh: () => void;
 }
 
@@ -47,7 +47,13 @@ export function TaskControls({
         placeholder="All statuses"
         data={STATUS_OPTIONS}
         value={statusFilter ?? null}
-        onChange={(value) => onStatusFilterChange(value ?? "")}
+        onChange={(value) =>
+          onStatusFilterChange(
+            value && STATUS_OPTIONS.includes(value as TaskStatus)
+              ? (value as TaskStatus)
+              : undefined,
+          )
+        }
         clearable
       />
     </Stack>