fix(storage): migrate history from legacy iCloud path on upgrade

Users upgrading from v0.5.4 had their history silently dropped because
the iCloud auto-detection was removed without a migration path. On first
launch, the local DB was empty while the old iCloud DB still had all
their data.

On macOS, when no sync replica is configured, open_and_migrate() now
checks the old iCloud auto-detected path and pulls from it if it has
newer data than the local DB. Uses the same try_pull_from_replica path
so the copy is atomic and idempotent.

Bump version to v0.5.6

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

Author: program247365

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "looper"
-version = "0.5.5"
+version = "0.5.6"
 authors = ["Kevin B. Ridgway <kridgway@gmail.com>"]
 edition = "2018"
 

Cargo.toml

@@ -159,7 +159,16 @@ impl Storage {
                     reason: err.to_string(),
                 }),
             },
-            None => None,
+            None => {
+                // One-time legacy migration for users upgrading from v0.5.4 and earlier:
+                // their history lives in the old iCloud auto-detected path. Pull silently
+                // if that path exists and the local DB has no newer data.
+                #[cfg(target_os = "macos")]
+                if let Some(legacy) = legacy_icloud_db_path() {
+                    let _ = try_pull_from_replica(&legacy, &local_path);
+                }
+                None
+            }
         };
 
         let storage = Self::open_and_migrate_at(local_path)?;
@@ -467,6 +476,13 @@ fn checkpoint_db(path: &Path) -> Result<()> {
     Ok(())
 }
 
+#[cfg(target_os = "macos")]
+fn legacy_icloud_db_path() -> Option<PathBuf> {
+    let home = directories::UserDirs::new()?.home_dir().to_path_buf();
+    let path = home.join("Library/Mobile Documents/com~apple~CloudDocs/looper/looper.sqlite3");
+    if path.exists() { Some(path) } else { None }
+}
+
 fn sync_folder_config_path() -> Option<PathBuf> {
     directories::BaseDirs::new()
         .map(|b| b.home_dir().join(".config").join("looper").join("sync_folder"))