refactor(web-panel): update architecture + cheat i18n

Reorganize the panel around product capabilities and integrate the
remote i18n feature from origin/master into the new structure.

- Restructure src into capability features (app, trainer, library,
  remote-session, appearance, shared); move the bridge to bridge/src.
- Add lingui-based UI localization and wrap remaining user-facing
  strings (Trans / msg macros); fix the 'END В·' mojibake.
- Port WeMod cheat-metadata i18n: capture the access token from the
  snapshot's renderer in the bridge and fetch localized trainer_meta
  in remote-session.i18n; guarantee snapshot sync on token failure.
- Wire vitest to the app's lingui/preact pipeline (mergeConfig).

web-panel/protocol/web-contract.json

@@ -0,0 +1,13 @@
+{
+  "protocolVersion": 1,
+  "clientVersion": "0.2.0",
+  "serverVersion": "0.2.0-wand",
+  "defaultRemoteHost": "0.0.0.0",
+  "defaultRemotePort": 3223,
+  "portScanRange": 30,
+  "basePath": "/remote/",
+  "assetsPath": "/remote/assets/",
+  "webSocketPath": "/remote/ws",
+  "healthPath": "/remote/api/health",
+  "installedAppsPath": "/remote/api/installed-apps"
+}