feat: Add task deletion with shift+click auto-confirm

- Add deleteTask tRPC mutation (repo already had delete method)
- Add X button to TaskRow, hidden until hover, with confirmation dialog
- Shift+click bypasses confirmation for fast bulk deletion
- Invalidates listInitiativeTasks on success
- Document shift+click pattern in CLAUDE.md as standard for destructive actions

src/trpc/routers/task.ts

@@ -143,6 +143,14 @@ export function taskProcedures(publicProcedure: ProcedureBuilder) {
         return tasks.filter((t) => t.category !== 'detail');
       }),
 
+    deleteTask: publicProcedure
+      .input(z.object({ id: z.string().min(1) }))
+      .mutation(async ({ ctx, input }) => {
+        const taskRepository = requireTaskRepository(ctx);
+        await taskRepository.delete(input.id);
+        return { success: true };
+      }),
+
     approveTask: publicProcedure
       .input(z.object({ taskId: z.string().min(1) }))
       .mutation(async ({ ctx, input }) => {