fix(ui): library restore no longer re-fires change on synced dropdowns

restoreLibrarySelection() ran on every page load via the header's
x-init and always dispatched a synthetic `change` on #library-select
after setting its value. On SSR pages the dropdown already renders the
stored library (setSelectedLibrary keeps the cookie in sync and
resolveLibrary renders from it), so the synthetic event re-ran the
page's switch handler, whose fetches are hardcoded to page 1 /
offset 0 — stomping freshly rendered content.

Visible impact: the /series paginator snapped back to page 1 on every
navigation whenever a specific library was stored (All Libraries
short-circuits restore, which is why it only failed per-library).
Silent impact: dashboard and collection-detail pages re-fetched their
content on every single load.

The restore now re-fires `change` only when the dropdown genuinely
drifted from storage; the common synced case is a visual no-op.

web/src/header.ts

@@ -32,6 +32,14 @@ const restoreLibrarySelection = (): void => {
     if (dropdown) {
       const option = dropdown.querySelector(`option[value="${savedLibrary}"]`);
       if (option) {
+        // SSR pages already render the select with the stored library
+        // (setSelectedLibrary keeps the cookie in sync and resolveLibrary
+        // renders from it). Re-firing `change` here made every page load
+        // re-run the page's switch handler — which re-fetches content at
+        // hardcoded page 1 / offset 0 and stomps URL-tracked state (this
+        // broke the /series paginator: page 2 snapped back to page 1).
+        // Only re-fire when the select actually drifted from storage.
+        if (dropdown.value === savedLibrary) return;
         dropdown.value = savedLibrary;
         dropdown.dispatchEvent(new Event("change", { bubbles: true }));
         console.log("Restored library selection:", savedLibrary);