fix: correct relative imports after component reorganization

Fixed import paths for 43 components moved into features/ directories.
Key fixes:
- api/, types/, hooks/, state/, utils/ imports need ../../../ from features/*/
- components/ imports need ../../ from features/*/
- Cross-feature imports use relative paths (e.g., ../tool/tools-bottom-sheet)
- app-shell.tsx updated to import from features/ subdirectories

Frontend typecheck now passes except for one pre-existing error:
xterm-addon-webgl missing type declarations.

Quality gates: ruff passed on backend, py_compile passed on all backend files.

apps/web/src/components/features/notification/notification-item.tsx

@@ -1,6 +1,6 @@
-import { Icon } from "./icon";
-import { formatRelativeTime } from "../utils/time";
-import type { NotificationItem as NotificationItemType } from "../api/notifications";
+import { Icon } from "../../icon";
+import { formatRelativeTime } from "../../../utils/time";
+import type { NotificationItem as NotificationItemType } from "../../../api/notifications";
 
 export interface NotificationItemProps {
 	notification: NotificationItemType;
@@ -8,7 +8,7 @@ export interface NotificationItemProps {
 	onDismiss: (id: string) => void;
 }
 
-import type { IconName } from "../utils/icons";
+import type { IconName } from "../../../utils/icons";
 
 const severityIconMap: Record<string, IconName> = {
 	info: "info",