feat(android): settings live on the device, dark theme, and the app is called Coffre

URL and token are no longer constants. They sit in settings.bin, sealed with the no-auth Keystore AES key - deliberately weaker than the vault: they must be readable to rebuild a vault that no longer exists, and a bearer token only opens ENCRYPTED data, worthless without the sync password that stays in the guarded vault. Retyping 64 hex characters after every cache purge was the real risk: the risk of writing them down elsewhere. They are saved only after a fetch that worked - proven settings, not typed ones.

The token and sync password moved to the gitignored local include, as first-run defaults only. Tracked source now carries no secret, and leaving them empty is a viable configuration: the app asks.

Theme: Delphi's Dark.style, copied into the repo and linked as a resource rather than deployed as a file - this project's deployment puts nothing beside the app, which is the same hole that forces the manifest and dex staging. A failure to load is never fatal; the default look is ugly but works.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

android-client/README.md

@@ -196,6 +196,13 @@ De quoi il a besoin, mis en place à la main sous `Android64\Debug\pmserverApk\`
 | `classes\*.dex` | `Android64\Debug\pmserverApk.classes\*.dex` |
 | `library\lib\arm64-v8a\libpmserverApk.so` | `Android64\Debug\libpmserverApk.so` |
 
+Le thème a besoin de sa ressource, **une fois** (MSBuild ne compile pas les
+`.rc` référencés par `{$R}` — c'est une commodité de l'EDI, pas du compilateur) :
+
+```bash
+cd android-client\theme && brcc32 theme.rc -fotheme.res
+```
+
 Ensuite `msbuild pmserverApk.dproj /p:Platform=Android64 /p:Config=Debug
 /t:Deploy` produit et signe `bin\pmserverApk.apk`, et `adb install -r` l'installe.
 Le correctif durable serait d'écrire ces entrées une fois dans le `.dproj`.