Update legal documents and localization for compliance and clarity

- Updated .env.example with legal operator details for compliance.
- Refactored Impressum, Privacy, and Terms pages to utilize a new LegalDocument component for improved structure and maintainability.
- Enhanced localization files to include legal content in both German and English, ensuring accurate representation of legal information.
- Improved i18n handling to support locale detection from Accept-Language headers.

apps/webui/src/messages/en.json

@@ -770,35 +770,5 @@
     "updatesTitle": "Updates & incidents",
     "updatesEmpty": "No entries yet.",
     "incident": "Incident"
-  },
-  "legal": {
-    "navTitle": "Legal",
-    "scaffoldNotice": "Scaffold text — review and adapt before production use.",
-    "impressum": {
-      "title": "Legal notice",
-      "intro": "Information according to German Telemedia Act (DDG).",
-      "name": "Operator",
-      "address": "Address",
-      "email": "Email",
-      "phone": "Phone",
-      "notConfigured": "Operator details missing. Set LEGAL_OPERATOR_NAME, LEGAL_OPERATOR_ADDRESS, and LEGAL_OPERATOR_EMAIL in .env.",
-      "p1": "The operator named above is responsible for this website and for running Nexumi.",
-      "p2": "We are not responsible for external links. Operators of linked sites are solely responsible for their content."
-    },
-    "privacy": {
-      "title": "Privacy policy",
-      "p1": "Nexumi processes Discord data as required to operate the bot and dashboard (e.g. guild IDs, user IDs, moderation cases, module settings).",
-      "p2": "Dashboard login uses Discord OAuth2 (identify and guilds scopes). Session data is stored in Redis.",
-      "p3": "Data is stored in our PostgreSQL database. Retention can be configured per module or via deletion requests.",
-      "p4": "Data is not shared with third parties except where technically required (e.g. Discord API, optional Sentry).",
-      "p5": "Data subjects may request access, correction, and deletion via the contact in the legal notice or bot commands where available."
-    },
-    "terms": {
-      "title": "Terms of service",
-      "p1": "Nexumi is provided as a Discord bot. Use is at your own risk.",
-      "p2": "Abuse, spam, or violations of Discord Terms of Service may result in blacklisting.",
-      "p3": "We do not guarantee uninterrupted service. Maintenance windows are announced when possible.",
-      "p4": "German law applies unless mandatory consumer protection rules require otherwise."
-    }
   }
 }