feat: mod platform integration (showcase, cloud slots, cloud screen, server-side unlink)

Mod:
- %config slots/pull/publish/unpublish for the four cloud slots
- %showcase [new|popular] [page] | load | copy, with number references
- %cloud opens a CloudScreen (link/unlink, slots, showcase) on vanilla widgets
- %config load IDDQD works offline (everything off except ChinaHat)
- default backend URL is now the production gateway
- shared ConfigRemoteApplier and ClientThread replace per-class copies
- %link unlink revokes the link on the server, then clears the local token

Backend:
- POST /device/revoke (RFC 7009 style self-revoke, always 204), rate limited
  to 10/min per IP at the gateway

CloudScreen is compiled but has not been opened in a running client yet.

mod/src/main/resources/assets/lovisual/lang/en_us.json

@@ -3287,7 +3287,7 @@
   "setting.nointeract.only_kill_aura": "Only with KillAura",
   "command.addons.description": "Lists, scans, enables, or disables client addons.",
   "command.bind.description": "Changes module key binds and lists existing binds.",
-  "command.config.description": "Saves, reloads, or locates the client config; uploads it to a cloud slot or loads a shared code.",
+  "command.config.description": "Saves, reloads, or locates the client config; uploads, lists and pulls cloud slots, loads a shared code, publishes to the showcase.",
   "command.coordinates.description": "Shows the current player coordinates.",
   "command.enemy.description": "Manages the client enemy list.",
   "command.gps.description": "Sets or clears the Gps compass target.",
@@ -3467,6 +3467,8 @@
   "setting.kineticlyrics.time_offset_ms.desc": "Shifts lyric timing vs the audible audio (ms). Positive = text later. Player position leads the speakers (Bluetooth: 0.5-1s+), so a negative default compensates. Tune with debug mode if it still drifts.",
   "setting.kineticlyrics.arc_spread.desc": "How wide around your view lines may spawn; automatically clamped to your real horizontal FOV.",
   "command.link.description": "Link this client to your LoVisual account, or check/unlink an existing link.",
+  "command.showcase.description": "Browses the public config showcase, tries a listing, or copies it into a cloud slot.",
+  "command.cloud.description": "Opens the cloud screen: account link, your four config slots and the showcase.",
   "setting.main_config.menuLayout": "Main menu style",
   "setting.main_config.menuLayout.option.orbs": "Orbs",
   "setting.main_config.menuLayout.option.hero": "Hero",