Fix SQLite recovery and preserve provider conversation context

Persist exact provider history and archived tool results independently of
terminal scrollback, and retain them when active run checkpoints are cleared.
Keep conversation and session saving independent of automatic reopening.

Deduplicate only committed session snapshots, retry transient SQLite write
contention, and enqueue conversation updates before writer shutdown. Recover
healthy startup data independently and protect unread records by disabling
writes with a persistent warning after an incomplete restore. Retain local
transcript pane conversation links across restarts.

Add regression coverage for SQLite failures, context round trips, legacy
fallbacks, and transcript snapshots.

app/src/lib.rs

@@ -2829,6 +2829,24 @@ fn launch(ctx: &mut galaxyui::AppContext, app_state: Option<AppState>, launch_mo
                 timer.mark_interval_end("WINDOWS_CREATED");
             });
 
+            #[cfg(feature = "local_fs")]
+            if matches!(launch_mode, LaunchMode::App { .. })
+                && PersistenceWriter::as_ref(ctx).sender().is_none()
+            {
+                let windows: Vec<_> = ctx.window_ids().collect();
+                for window_id in windows {
+                    ToastStack::handle(ctx).update(ctx, |toasts, ctx| {
+                        toasts.add_persistent_toast(
+                            DismissibleToast::error(
+                                "Galaxy could not restore all local data. Saving is disabled to protect existing data. Check the logs and restart after resolving the problem.".to_string(),
+                            ),
+                            window_id,
+                            ctx,
+                        );
+                    });
+                }
+            }
+
             // TODO(ben): We should skip this for LaunchMode::Test.
             #[cfg(any(target_os = "macos", target_os = "windows"))]
             {