chore(format): run prettier over src/ and scripts/

Formatting was configured but never enforced: `bun run format:check`
reported 199 unformatted files and ran in no workflow and in no git hook,
so .prettierrc (printWidth 100, trailing commas) described an intention
rather than the tree.

This is the one-time sweep that makes the check gateable. Whitespace and
token-reflow only -- no behavioural change: `bun run check` reports 0
errors and all 1053 frontend tests pass before and after.

Kept out of every other commit on purpose. A 199-file diff mixed with
real changes is unreviewable, and the next commit turns format:check
into a hard CI gate so this cannot silently accumulate again.

src/lib/components/library/ClearHistoryButton.svelte

@@ -43,7 +43,7 @@
       !confirm(
         `Erase watch history for ${subject}?\n\n` +
           "Every episode is marked unwatched and resume positions are cleared. " +
-          "This cannot be undone."
+          "This cannot be undone.",
       )
     ) {
       return;
@@ -55,9 +55,7 @@
       onCleared?.();
     } catch (e) {
       log.error("Failed to clear watch history:", e);
-      alert(
-        `Could not clear watch history: ${e instanceof Error ? e.message : String(e)}`
-      );
+      alert(`Could not clear watch history: ${e instanceof Error ? e.message : String(e)}`);
     } finally {
       busy = false;
     }
@@ -81,11 +79,7 @@
              {size === 'lg' ? 'w-5 h-5' : 'w-4 h-4'}"
     ></div>
   {:else}
-    <svg
-      class={size === "lg" ? "w-5 h-5" : "w-4 h-4"}
-      fill="currentColor"
-      viewBox="0 0 24 24"
-    >
+    <svg class={size === "lg" ? "w-5 h-5" : "w-4 h-4"} fill="currentColor" viewBox="0 0 24 24">
       <path
         d="M13 3a9 9 0 0 0-9 9H1l3.89 3.89.07.14L9 12H6a7 7 0 1 1 7 7c-1.93
            0-3.68-.79-4.94-2.06l-1.42 1.42A8.95 8.95 0 0 0 13 21a9 9 0 0 0