Add Playwright a11y tests, structured data, and reduced motion support

- Add Playwright tests with axe-core (42 tests across 3 browsers)
- Add prefers-reduced-motion support to NebulaField
- Add JSON-LD structured data (Organization schema)
- Add canonical URLs to all pages
- Consolidate TODO files, update README

apps/web/playwright.config.ts

@@ -0,0 +1,33 @@
+import { defineConfig, devices } from "@playwright/test";
+
+export default defineConfig({
+  testDir: "./tests",
+  fullyParallel: true,
+  forbidOnly: !!process.env.CI,
+  retries: process.env.CI ? 2 : 0,
+  workers: process.env.CI ? 1 : undefined,
+  reporter: "html",
+  use: {
+    baseURL: "http://localhost:3000",
+    trace: "on-first-retry",
+  },
+  projects: [
+    {
+      name: "chromium",
+      use: { ...devices["Desktop Chrome"] },
+    },
+    {
+      name: "firefox",
+      use: { ...devices["Desktop Firefox"] },
+    },
+    {
+      name: "webkit",
+      use: { ...devices["Desktop Safari"] },
+    },
+  ],
+  webServer: {
+    command: "pnpm run start",
+    url: "http://localhost:3000",
+    reuseExistingServer: !process.env.CI,
+  },
+});