Implement encoding and decoding for Windows-invalid characters in file names

- Added `encode_path_name` and `decode_path_name` functions to handle encoding and decoding of invalid characters.
- Updated `SyncbackRules` to include an option for encoding Windows-invalid characters during syncback.
- Modified `name_for_inst` to conditionally encode invalid characters based on the new option.
- Adjusted `ServeSession` and `InstanceContext` to support the new encoding feature.
- Updated tests and snapshots to reflect changes in encoding behavior.

src/syncback/mod.rs

@@ -409,6 +409,12 @@ pub struct SyncbackRules {
     /// generally a better UX.
     #[serde(skip_serializing_if = "Option::is_none")]
     create_ignore_dir_paths: Option<bool>,
+    /// Whether to encode Windows-invalid characters in file names during
+    /// syncback. Characters like `<`, `>`, `:`, `"`, `/`, `\`, `|`, `?`, `*`
+    /// will be encoded as `%LT%`, `%GT%`, `%COLON%`, etc.
+    /// Defaults to `false`.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    encode_windows_invalid_chars: Option<bool>,
 }
 
 impl SyncbackRules {
@@ -432,6 +438,13 @@ impl SyncbackRules {
 
         Ok(globs)
     }
+
+    /// Returns whether Windows-invalid characters should be encoded in file
+    /// names during syncback. Defaults to `false`.
+    #[inline]
+    pub fn encode_windows_invalid_chars(&self) -> bool {
+        self.encode_windows_invalid_chars.unwrap_or(false)
+    }
 }
 
 fn is_valid_path(globs: &Option<Vec<Glob>>, base_path: &Path, path: &Path) -> bool {