Add global /about command and configuration

- Introduced `BotAboutConfig` model for managing the global `/about` message in the owner panel.
- Implemented the `/about` command with localization support and integrated it into the help catalog.
- Enhanced the dashboard with a new owner section for configuring the `/about` message type and content.
- Updated components to handle the new command and its interactions, including support for different message formats (TEXT, EMBED, COMPONENTS_V2).
- Added localization entries for the `/about` command in English and German, improving accessibility for users.
- Documented the implementation in the phase tracking documentation for future reference.

apps/webui/src/messages/en.json

@@ -968,6 +968,7 @@
       "flags": "Feature flags",
       "premium": "Premium",
       "presence": "Presence",
+      "about": "About",
       "team": "Team",
       "jobs": "Jobs",
       "changelog": "Changelog",
@@ -1070,6 +1071,26 @@
         "Competing": "Competing in"
       }
     },
+    "about": {
+      "title": "About /about",
+      "subtitle": "Content of the global /about reply in Discord.",
+      "editorTitle": "About message",
+      "editorDescription": "TEXT, embed, or Components V2 — shown for /about on every server.",
+      "enabled": "About enabled",
+      "enabledHint": "When off, /about replies with a disabled notice.",
+      "messageType": "Message type",
+      "type": {
+        "TEXT": "Text",
+        "EMBED": "Embed",
+        "COMPONENTS_V2": "Components V2"
+      },
+      "content": "Text content",
+      "contentPlaceholder": "Short text about Nexumi…",
+      "embed": "Embed",
+      "components": "Components V2",
+      "componentsHint": "Role actions apply in the server where /about is used. No role picker here without a guild context.",
+      "readOnly": "View only — saving requires Admin owner role or higher."
+    },
     "team": {
       "title": "Team",
       "subtitle": "Additional owners/admins with graded permissions.",