feat: paginate list views, fix stale page titles, tidy admin filter bar

Bundle of small UI/UX fixes plus a build hygiene tweak.

* List pagination — Home (`/`) and `/authors/[id]` silently capped at
  the backend default of 50 with no UI to advance. New reusable
  `Pager.svelte` (Prev/Next + numbered with ellipsis), URL-synced
  `?page=N`, and filter/search/sort reset to page 1 so users aren't
  stranded on an out-of-range page. Count label now shows a range
  ("Showing 51–100 of 237").

* Stale page title — Pages without a `<svelte:head><title>` left the
  document title at whatever the last manga / author / collection page
  set it to. Move static-route titles into a route-id → title map in
  the root layout and invert every dynamic title to brand-first
  (`Mangalord | {X}`) for consistency.

* Admin filter bar — `/admin/mangas` search input had `flex: 1` and
  ballooned across the row, shoving the sync-state select + Search
  button to the far right. Cap at 24rem, vertical-align the row, and
  promote the previously aria-only "Sync state" label to visible text.

* Build hygiene — `backend/target` had grown to 68 GiB. Cleaned and
  added `[profile.dev] debug = "line-tables-only"` (and `[profile.test]`
  too) to cut future dev builds by ~50–70% while keeping line numbers
  in backtraces.

Also: configure vitest to resolve Svelte's browser entry so
`@testing-library/svelte` can mount components in jsdom — needed for
the new `Pager.svelte.test.ts`.

Bump 0.48.0 -> 0.49.1.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/Pager.svelte.test.ts

@@ -0,0 +1,77 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { render, screen, cleanup } from '@testing-library/svelte';
+import Pager from './Pager.svelte';
+
+afterEach(() => cleanup());
+
+describe('Pager', () => {
+    it('renders nothing when totalPages <= 1', () => {
+        const { container } = render(Pager, { props: { page: 1, totalPages: 1, onChange: () => {} } });
+        expect(container.querySelector('nav')).toBeNull();
+    });
+
+    it('disables Prev on the first page and Next on the last', () => {
+        const { rerender } = render(Pager, {
+            props: { page: 1, totalPages: 5, onChange: () => {} }
+        });
+        expect((screen.getByRole('button', { name: /prev/i }) as HTMLButtonElement).disabled).toBe(true);
+        expect((screen.getByRole('button', { name: /next/i }) as HTMLButtonElement).disabled).toBe(false);
+
+        rerender({ page: 5, totalPages: 5, onChange: () => {} });
+        expect((screen.getByRole('button', { name: /prev/i }) as HTMLButtonElement).disabled).toBe(false);
+        expect((screen.getByRole('button', { name: /next/i }) as HTMLButtonElement).disabled).toBe(true);
+    });
+
+    it('marks the current page button as aria-current', () => {
+        render(Pager, { props: { page: 3, totalPages: 5, onChange: () => {} } });
+        const current = screen.getByRole('button', { name: /go to page 3/i });
+        expect(current.getAttribute('aria-current')).toBe('page');
+    });
+
+    it('fires onChange with the clicked page number', async () => {
+        const onChange = vi.fn();
+        render(Pager, { props: { page: 1, totalPages: 5, onChange } });
+        screen.getByRole('button', { name: /go to page 3/i }).click();
+        expect(onChange).toHaveBeenCalledWith(3);
+    });
+
+    it('Prev decrements and Next increments via onChange', () => {
+        const onChange = vi.fn();
+        render(Pager, { props: { page: 3, totalPages: 5, onChange } });
+        screen.getByRole('button', { name: /prev/i }).click();
+        screen.getByRole('button', { name: /next/i }).click();
+        expect(onChange).toHaveBeenNthCalledWith(1, 2);
+        expect(onChange).toHaveBeenNthCalledWith(2, 4);
+    });
+
+    it('shows every page button when totalPages <= 7', () => {
+        render(Pager, { props: { page: 4, totalPages: 7, onChange: () => {} } });
+        for (let n = 1; n <= 7; n++) {
+            expect(screen.getByRole('button', { name: new RegExp(`go to page ${n}$`, 'i') })).toBeTruthy();
+        }
+    });
+
+    it('collapses middle pages with ellipsis when totalPages > 7 and current is in the middle', () => {
+        render(Pager, { props: { page: 10, totalPages: 24, onChange: () => {} } });
+        // First and last are always shown
+        expect(screen.getByRole('button', { name: /go to page 1$/i })).toBeTruthy();
+        expect(screen.getByRole('button', { name: /go to page 24$/i })).toBeTruthy();
+        // Current and direct neighbours are shown
+        expect(screen.getByRole('button', { name: /go to page 9$/i })).toBeTruthy();
+        expect(screen.getByRole('button', { name: /go to page 10$/i })).toBeTruthy();
+        expect(screen.getByRole('button', { name: /go to page 11$/i })).toBeTruthy();
+        // Distant pages are NOT rendered as buttons
+        expect(screen.queryByRole('button', { name: /go to page 2$/i })).toBeNull();
+        expect(screen.queryByRole('button', { name: /go to page 23$/i })).toBeNull();
+        // Ellipsis appears on both sides
+        const ellipses = screen.getAllByText('…');
+        expect(ellipses.length).toBeGreaterThanOrEqual(2);
+    });
+
+    it('does not duplicate boundary buttons when current is near the edge', () => {
+        render(Pager, { props: { page: 2, totalPages: 20, onChange: () => {} } });
+        // Each page button rendered should be unique — no duplicate "go to page 1"
+        const first = screen.getAllByRole('button', { name: /go to page 1$/i });
+        expect(first.length).toBe(1);
+    });
+});