Enhance VFS watch functionality and introduce recording mode

- Updated the `watch` method in `VfsBackend` to accept a `recursive` parameter, allowing for more flexible directory watching.
- Implemented a recording mode in the `Vfs` struct to track accessed paths without immediately watching them, improving performance during read operations.
- Added tests to verify the behavior of the new recording mode and ensure correct path tracking.
- Enhanced the `StdBackend` and `NoopBackend` implementations to support the updated watch functionality.

These changes aim to improve the VFS's ability to manage file system events and enhance user control over watching behavior.

src/snapshot/metadata.rs

@@ -155,6 +155,8 @@ pub struct InstanceContext {
     pub path_ignore_rules: Arc<Vec<PathIgnoreRule>>,
     #[serde(skip_serializing_if = "Vec::is_empty")]
     pub sync_rules: Vec<SyncRule>,
+    #[serde(skip)]
+    pub sync_scripts_only: bool,
 }
 
 impl InstanceContext {
@@ -162,6 +164,7 @@ impl InstanceContext {
         Self {
             path_ignore_rules: Arc::new(Vec::new()),
             sync_rules: Vec::new(),
+            sync_scripts_only: false,
         }
     }