perf: fix slow page loads and gate performance in CI

- Ship one hashed Tailwind stylesheet instead of two (one render-blocking)
- Compress responses in-app (brotli/gzip, streaming-safe) and precompress
  the node build so local and CI measurements match production
- Validate the Supabase session once per request
- Render the homepage immediately and stream public stats
- Stream a Pokedex's entries with the page instead of fetching after
  hydration, running the rows and count queries in parallel
- Shrink the avatar and offline placeholder images, fix layout shift,
  contrast, link names and missing meta descriptions
- Add Lighthouse CI (mobile + desktop) with score and metric budgets,
  bundle-size budgets in the build tests, and signed-in speed scenarios

tests/unit/combinedDataService.test.ts

@@ -0,0 +1,77 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import type { Pokedex } from '$lib/models/Pokedex';
+
+const findCombinedData = vi.fn();
+const countCombinedData = vi.fn();
+const constructed: unknown[][] = [];
+
+vi.mock('$lib/repositories/CombinedDataRepository', () => ({
+	default: class {
+		constructor(...args: unknown[]) {
+			constructed.push(args);
+		}
+		findCombinedData = findCombinedData;
+		countCombinedData = countCombinedData;
+	}
+}));
+vi.mock('$lib/services/PokedexDexScopeService', () => ({
+	resolveDexScopes: vi.fn(async () => ['national'])
+}));
+
+const { loadCombinedDataPage } = await import('$lib/services/CombinedDataService');
+
+const supabase = {} as never;
+const pokedex = { _id: 'dex-1', gameScope: 'Black' } as unknown as Pokedex;
+
+describe('loadCombinedDataPage', () => {
+	beforeEach(() => {
+		constructed.length = 0;
+		findCombinedData.mockReset().mockResolvedValue([{ id: 'row' }]);
+		countCombinedData.mockReset().mockResolvedValue(45);
+	});
+
+	it("defaults to the Pokédex's game scope and reports pagination", async () => {
+		const result = await loadCombinedDataPage(supabase, 'user-1', pokedex, {
+			page: 2,
+			limit: 20,
+			enableForms: true
+		});
+
+		expect(constructed).toEqual([[supabase, 'user-1', 'dex-1']]);
+		expect(findCombinedData).toHaveBeenCalledWith('user-1', 2, 20, true, '', 'Black', ['national']);
+		expect(countCombinedData).toHaveBeenCalledWith(true, '', 'Black', ['national']);
+		expect(result).toEqual({
+			combinedData: [{ id: 'row' }],
+			totalPages: 3,
+			currentPage: 2,
+			totalCount: 45
+		});
+	});
+
+	it('prefers an explicit game and region filter', async () => {
+		await loadCombinedDataPage(supabase, 'user-1', pokedex, {
+			page: 1,
+			limit: 9999,
+			enableForms: false,
+			region: 'unova',
+			game: 'White'
+		});
+
+		expect(countCombinedData).toHaveBeenCalledWith(false, 'unova', 'White', ['national']);
+	});
+
+	it('runs the rows and count queries at the same time', async () => {
+		let releaseRows: (rows: unknown[]) => void = () => {};
+		findCombinedData.mockReturnValue(new Promise((resolve) => (releaseRows = resolve)));
+		const pending = loadCombinedDataPage(supabase, 'user-1', pokedex, {
+			page: 1,
+			limit: 10,
+			enableForms: false
+		});
+
+		// The count starts before the rows query has finished.
+		await vi.waitFor(() => expect(countCombinedData).toHaveBeenCalled());
+		releaseRows([]);
+		await expect(pending).resolves.toMatchObject({ totalCount: 45, totalPages: 5 });
+	});
+});