Command framework replaced: ACF → Cloud

The plugin no longer runs on ACF, which is no longer maintained, but on Cloud 2.x instead.

• Nothing changes for your permissions or command paths: /ah, /hdv and all 13 subcommands are exactly where they were.
• /ah help has a new layout, generated by Cloud.
• /ah help <query> now shows the help for a single command.
• /ah admin reload now reloads the language file too — it used to only be read at startup.
• /ah admin migrate now refuses a migration version it doesn't recognize (and tab-completes the ones it does), instead of silently doing nothing and reporting success.
• /ah sell now refuses NaN or Infinity as a price before touching your inventory.
• Minimum server version is now Paper 1.16.5.

Language files

• Language files are now versioned and updated automatically, exactly like the other configuration files — no action required.
• Your customised texts are preserved; a lang_<code>.yml.bak backup is kept next to the file before its first automatic update.
• A language the plugin doesn't ship (e.g. lang_de.yml) keeps every key you wrote and falls back to English for the rest.
• Chinese (lang_zhcn.yml) gained 3 messages that were silently never sent before (max_price, clear_cache, migrate).

Other

• Various dependency updates and internal hardening (CodeQL findings addressed).