docs: readme, schnellstart, bebilderte anleitung und changelog 0.1.0

QUICKSTART fuehrt von null zur laufenden Instanz und enthaelt die
vollstaendige Nginx-Proxy-Manager-Konfiguration - inklusive der beiden
Stellen, an denen es sonst klemmt: client_max_body_size fuer grosse
Anleitungs-PDFs und X-Forwarded-For fuer das Rate-Limit.

Die Anleitung ist bebildert. Die 16 Screenshots entstehen automatisiert
mit `pnpm screenshots` gegen das Produktions-Image im Container, nicht
gegen den Dev-Server: der brach unter Last reproduzierbar mit
ChunkLoadError ab, und die Bilder zeigen so ohnehin genau das, was nach
`docker compose up` zu sehen ist.

Nebenbei behoben: in der Mehrfachauswahl verdeckte die Aktionsleiste die
letzte Kachelreihe.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

playwright.screenshots.config.ts

@@ -1,23 +1,31 @@
+import path from 'node:path';
 import { defineConfig, devices } from '@playwright/test';
 
 /**
  * Produces the screenshots for docs/ANLEITUNG.md.
  *
- * Kept apart from the smoke test on purpose: this run needs seeded example
- * data and writes files into the repository, which a test never should.
+ * Runs against the production container, not the dev server: the dev server
+ * compiles routes on demand, which made the capture run flaky, and the manual
+ * should show exactly what a user gets after `docker compose up`.
  *
  *   pnpm screenshots
  */
 const PORT = 3220;
 const BASE_URL = `http://localhost:${PORT}`;
 
+// Docker wants forward slashes, also on Windows.
+const dataDir = path.resolve(process.cwd(), 'data-shots').replace(/\\/g, '/');
+
 export default defineConfig({
   testDir: './e2e',
   testMatch: 'screenshots.spec.ts',
-  globalSetup: './e2e/screenshots-setup.ts',
   fullyParallel: false,
   workers: 1,
-  timeout: 240_000,
+  // The run registers a user, so a second attempt would start from a state
+  // that no longer matches the script.
+  retries: 0,
+  timeout: 300_000,
+  expect: { timeout: 30_000 },
   reporter: 'list',
   use: {
     baseURL: BASE_URL,
@@ -27,18 +35,19 @@ export default defineConfig({
     ...devices['Pixel 7'],
   },
   webServer: {
-    command: `pnpm exec next dev -p ${PORT}`,
+    command: [
+      'docker run --rm --name bricktrack-shots',
+      `-p ${PORT}:3000`,
+      `-e BASE_URL=${BASE_URL}`,
+      '-e BETTER_AUTH_SECRET=screenshot-run-secret-0123456789abcdefgh',
+      '-e TZ=Europe/Berlin',
+      `-v "${dataDir}:/data"`,
+      'bricktrack:shots',
+    ].join(' '),
     url: `${BASE_URL}/api/health`,
     reuseExistingServer: false,
     timeout: 180_000,
     stdout: 'pipe',
     stderr: 'pipe',
-    env: {
-      NODE_ENV: 'development',
-      DATA_DIR: './data-shots',
-      BASE_URL,
-      BETTER_AUTH_SECRET: 'screenshot-run-secret-0123456789abcdefgh',
-      MAX_UPLOAD_MB: '25',
-    },
   },
 });