chore: format the tree and clear ruff's findings

Applies ruff format, ruff check --fix and prettier, so CI can gate on all three.
The surviving unused imports were all re-exports in __init__.py, now covered by a
per-file ignore; the pdf.js viewer and the generated openapi types join the
vendored code that eslint and prettier already skip.

frontend/src/lib/components/ui/popover/index.ts

@@ -1,8 +1,8 @@
-import Root from "./popover.svelte";
-import Close from "./popover-close.svelte";
-import Content from "./popover-content.svelte";
-import Trigger from "./popover-trigger.svelte";
-import Portal from "./popover-portal.svelte";
+import Root from './popover.svelte';
+import Close from './popover-close.svelte';
+import Content from './popover-content.svelte';
+import Trigger from './popover-trigger.svelte';
+import Portal from './popover-portal.svelte';
 
 export {
 	Root,
@@ -15,5 +15,5 @@ export {
 	Content as PopoverContent,
 	Trigger as PopoverTrigger,
 	Close as PopoverClose,
-	Portal as PopoverPortal,
+	Portal as PopoverPortal
 };