Refactor Reconciler tests and update path handling logic

- Updated test descriptions in `diff.spec.lua` and `diff.stress.spec.lua` to reflect changes in behavior regarding duplicate-named children in both real and virtual DOM contexts.
- Adjusted assertions to ensure that duplicate-named children are correctly removed or added based on the new matching logic.
- Refactored `hydrate.lua` and `matching.lua` to streamline the matching process by removing unnecessary parameters, enhancing clarity and maintainability.
- Updated metadata references in various test files to include the `.model.json5` extension for consistency in path handling.

These changes improve the accuracy of reconciliation tests and enhance the overall robustness of the Reconciler's path handling logic.

src/syncback/dedup_suffix.rs

@@ -58,11 +58,6 @@ pub fn parse_dedup_suffix(stem: &str) -> Option<(&str, u32)> {
     None
 }
 
-/// Checks whether a filename stem has a dedup suffix.
-pub fn has_dedup_suffix(stem: &str) -> bool {
-    parse_dedup_suffix(stem).is_some()
-}
-
 /// Builds a dedup'd filename from a base stem, optional suffix number, and
 /// extension.
 ///
@@ -180,13 +175,6 @@ mod tests {
         assert_eq!(parse_dedup_suffix("My Script~1"), Some(("My Script", 1)));
     }
 
-    #[test]
-    fn has_suffix() {
-        assert!(has_dedup_suffix("Foo~1"));
-        assert!(!has_dedup_suffix("Foo"));
-        assert!(!has_dedup_suffix("Foo~abc"));
-    }
-
     #[test]
     fn build_name_file() {
         assert_eq!(