chore: rename app from Solitaire Quest to Ferrous Solitaire

Updates all in-tree references:
- Android package: com.solitairequest.app → com.ferrousapp.solitaire
- APK name: solitaire-quest → ferrous-solitaire
- Data dir: solitaire_quest → ferrous_solitaire (across all 6 data modules + engine)
- Keyring service: solitaire_quest_server → ferrous_solitaire_server
- Android Keystore key: solitaire_quest_token_key → ferrous_solitaire_token_key
- Gitea repo: Rusty_Solitare → Ferrous-Solitaire (also fixes "Solitare" typo)
- Renamed pkg/solitaire-quest* → pkg/ferrous-solitaire*
- Updated ArgoCD, docker-compose, CI workflow, build script, all docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_data/src/achievements.rs

@@ -10,7 +10,7 @@ use std::path::{Path, PathBuf};
 
 pub use solitaire_sync::AchievementRecord;
 
-const APP_DIR_NAME: &str = "solitaire_quest";
+const APP_DIR_NAME: &str = "ferrous_solitaire";
 const FILE_NAME: &str = "achievements.json";
 
 /// Platform-specific default path for `achievements.json`.