SyncState migration to include sync_dir in unique index:

https://feedback.yaak.app/p/after-setting-up-sync-to-folder-there-is-a-yaml

src-tauri/migrations/20250531193722_sync-state-index.sql

@@ -0,0 +1,43 @@
+-- Add sync_dir to the unique index, or else it will fail if the user disables sync
+-- and re-enables it for a different directory.
+
+-- Step 1: Rename the existing table
+ALTER TABLE sync_states
+    RENAME TO sync_states_old;
+
+-- Step 2: Create the new table with the updated unique constraint
+CREATE TABLE sync_states
+(
+    id           TEXT                               NOT NULL PRIMARY KEY,
+    model        TEXT     DEFAULT 'sync_state'      NOT NULL,
+    workspace_id TEXT                               NOT NULL
+        REFERENCES workspaces ON DELETE CASCADE,
+    created_at   DATETIME DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    updated_at   DATETIME DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    flushed_at   DATETIME DEFAULT CURRENT_TIMESTAMP NOT NULL,
+    checksum     TEXT                               NOT NULL,
+    model_id     TEXT                               NOT NULL,
+    sync_dir     TEXT                               NOT NULL,
+    rel_path     TEXT                               NOT NULL
+);
+
+CREATE UNIQUE INDEX idx_sync_states_unique
+    ON sync_states (workspace_id, model_id, sync_dir);
+
+-- Step 3: Copy the data
+INSERT INTO sync_states (id, model, workspace_id, created_at, updated_at,
+                         flushed_at, checksum, model_id, sync_dir, rel_path)
+SELECT id,
+       model,
+       workspace_id,
+       created_at,
+       updated_at,
+       flushed_at,
+       checksum,
+       model_id,
+       sync_dir,
+       rel_path
+FROM sync_states_old;
+
+-- Step 4: Drop the old table
+DROP TABLE sync_states_old;