feat(workspace): full server + sync implementation, all tests green

- solitaire_server: Axum auth, sync push/pull, leaderboard, daily
  challenge, account deletion, JWT middleware, rate limiting via
  tower_governor, SQLite migrations, health endpoint
- solitaire_server: expose build_test_router (no rate limiting) so
  integration tests work without a peer IP in oneshot requests
- solitaire_sync: SyncPayload, merge logic, shared API types
- solitaire_data: SyncProvider trait, LocalOnlyProvider,
  SolitaireServerClient, auth_tokens keyring integration, blanket
  Box<dyn SyncProvider> impl
- solitaire_data/settings: derive Default on SyncBackend (clippy fix)
- .sqlx/: offline query cache so server compiles without a live DB
- sqlx: removed non-existent "offline" feature flag
- keyring v2: fixed Entry::new() returning Result<Entry>
- sqlx 0.8: all SQLite TEXT columns wrapped in Option<T>
- Integration tests: max_connections(1) on in-memory pool so all
  connections share the same schema

All 191 tests pass; cargo clippy -D warnings clean.

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

solitaire_engine/src/achievement_plugin.rs

@@ -124,7 +124,7 @@ fn evaluate_on_win(
         }
         record.unlock(now);
         changed = true;
-        unlocks.send(AchievementUnlockedEvent(def.id.to_string()));
+        unlocks.send(AchievementUnlockedEvent(record.clone()));
     }
 
     if changed {
@@ -201,7 +201,7 @@ mod tests {
         // Verify the event was emitted.
         let events = app.world().resource::<Events<AchievementUnlockedEvent>>();
         let mut cursor = events.get_cursor();
-        let fired: Vec<String> = cursor.read(events).map(|e| e.0.clone()).collect();
+        let fired: Vec<String> = cursor.read(events).map(|e| e.0.id.clone()).collect();
         assert!(fired.contains(&"first_win".to_string()));
     }
 
@@ -228,7 +228,7 @@ mod tests {
 
         let events = app.world().resource::<Events<AchievementUnlockedEvent>>();
         let mut cursor = events.get_cursor();
-        let fired: Vec<String> = cursor.read(events).map(|e| e.0.clone()).collect();
+        let fired: Vec<String> = cursor.read(events).map(|e| e.0.id.clone()).collect();
         assert!(
             !fired.contains(&"first_win".to_string()),
             "first_win must not re-fire on subsequent wins"