feat(pm): add bug-report button with screenshot annotation and admin panel

- New BugReport MongoDB model (comment, contact, userId, screenshot, pmState, status)
- POST /api/bug-reports — authenticated submit; emails emanuel@faktorxmensch.com on receipt
- GET/PATCH /api/admin/bug-reports + /[id] — admin list, detail with screenshot, status toggle
- /pm: "Bug" button in HUD captures viewport screenshot (html2canvas), shows annotation
  canvas where testers can draw arrows; submits comment + contact + state snapshot
- /admin: new "Bug Reports" tab with open-count badge, screenshot expand, "Erledigt" toggle,
  and "In /pm öffnen" link that restores captured engine state via ?restoreBugReport=<id>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -22,6 +22,7 @@
     "@pinia/nuxt": "^0.11.3",
     "dotenv": "^17.3.1",
     "fluent-ffmpeg": "^2.1.3",
+    "html2canvas": "^1.4.1",
     "nodemailer": "^8.0.1",
     "nuxt": "^4.3.1",
     "nuxt-aos": "^1.2.6",