Refactor project configuration to use .json format

- Replaced the legacy .json5 project file with a new .json format for `plugin.project.json`.
- Updated `build.rs` to prioritize the new .json format while maintaining backward compatibility with .json5.
- Made adjustments to the Confirming.lua file to enhance UI consistency.
- Improved metadata handling in snapshot middleware to support both modern and legacy file extensions.

src/snapshot_middleware/meta_file.rs

@@ -64,7 +64,7 @@ impl AdjacentMetadata {
             .or_else(|| file_stem.strip_suffix(".local"))
             .or_else(|| file_stem.strip_suffix(".legacy"))
             .unwrap_or(file_stem);
-        
+
         // Try modern extension first, then fall back to legacy
         let meta_path_json5 = path.with_file_name(format!("{base_name}.meta.json5"));
         let meta_path_json = path.with_file_name(format!("{base_name}.meta.json"));
@@ -503,14 +503,14 @@ pub fn dir_meta(vfs: &Vfs, path: &Path) -> anyhow::Result<Option<DirectoryMetada
         let metadata = DirectoryMetadata::from_slice(&meta_contents, meta_path_json5)?;
         return Ok(Some(metadata));
     }
-    
+
     // Legacy fallback: init.meta.json
     let meta_path_json = path.join("init.meta.json");
     if let Some(meta_contents) = vfs.read(&meta_path_json).with_not_found()? {
         let metadata = DirectoryMetadata::from_slice(&meta_contents, meta_path_json)?;
         return Ok(Some(metadata));
     }
-    
+
     Ok(None)
 }
 
@@ -526,7 +526,7 @@ pub fn file_meta(vfs: &Vfs, path: &Path, name: &str) -> anyhow::Result<Option<Ad
         let metadata = AdjacentMetadata::from_slice(&meta_contents, meta_path_json5)?;
         return Ok(Some(metadata));
     }
-    
+
     // Legacy fallback: .meta.json
     let mut meta_path_json = path.with_file_name(name);
     meta_path_json.set_extension("meta.json");
@@ -534,7 +534,7 @@ pub fn file_meta(vfs: &Vfs, path: &Path, name: &str) -> anyhow::Result<Option<Ad
         let metadata = AdjacentMetadata::from_slice(&meta_contents, meta_path_json)?;
         return Ok(Some(metadata));
     }
-    
+
     Ok(None)
 }
 

src/snapshot_middleware/mod.rs

@@ -133,9 +133,11 @@ fn get_dir_middleware<'path>(
             (Middleware::LegacyScriptDir, "init.legacy.luau"),
             (Middleware::CsvDir, "init.csv"),
             // Legacy extensions (for backwards compatibility)
+            // init.server.lua → Script with RunContext.Legacy (old emitLegacyScripts behavior)
+            // init.client.lua → LocalScript (old emitLegacyScripts behavior)
             (Middleware::ModuleScriptDir, "init.lua"),
-            (Middleware::ServerScriptDir, "init.server.lua"),
-            (Middleware::ClientScriptDir, "init.client.lua"),
+            (Middleware::LegacyScriptDir, "init.server.lua"),
+            (Middleware::LocalScriptDir, "init.client.lua"),
         ]
     });
 
@@ -431,8 +433,12 @@ pub fn default_sync_rules() -> &'static [SyncRule] {
             sync_rule!("*.model.json5", JsonModel, ".model.json5"),
             sync_rule!("*.json5", Json, ".json5", "*.meta.json5"),
             // Legacy Lua extensions (for backwards compatibility)
-            sync_rule!("*.server.lua", ServerScript, ".server.lua"),
-            sync_rule!("*.client.lua", ClientScript, ".client.lua"),
+            // .server.lua → Script with RunContext.Legacy (old emitLegacyScripts behavior)
+            // .client.lua → LocalScript (old emitLegacyScripts behavior)
+            // .plugin.lua → Script with RunContext.Plugin
+            sync_rule!("*.server.lua", LegacyScript, ".server.lua"),
+            sync_rule!("*.client.lua", LocalScript, ".client.lua"),
+            sync_rule!("*.plugin.lua", PluginScript, ".plugin.lua"),
             sync_rule!("*.lua", ModuleScript),
             // Legacy JSON extensions (for backwards compatibility)
             sync_rule!("*.project.json", Project, ".project.json"),

src/syncback/file_names.rs

@@ -38,7 +38,9 @@ pub fn name_for_inst<'old>(
             | Middleware::CsvDir
             | Middleware::ServerScriptDir
             | Middleware::ClientScriptDir
-            | Middleware::ModuleScriptDir => {
+            | Middleware::ModuleScriptDir
+            | Middleware::LocalScriptDir
+            | Middleware::LegacyScriptDir => {
                 let name = if encode_invalid_chars {
                     let encoded = encode_path_name(&new_inst.name);
                     // Validate for issues not fixed by encoding (trailing space/dot, control chars, reserved names)

src/syncback/snapshot.rs

@@ -306,7 +306,14 @@ impl<'sync> SyncbackSnapshot<'sync> {
 
 pub fn filter_out_property(inst: &Instance, prop_name: &str) -> bool {
     match inst.class.as_str() {
-        "Script" | "LocalScript" | "ModuleScript" => {
+        "Script" => {
+            // These properties shouldn't be set by scripts that are created via
+            // `$path` or via being on the file system.
+            // RunContext is filtered because it's encoded in the file extension:
+            // .server.luau → Server, .client.luau → Client, .plugin.luau → Plugin, .legacy.luau → Legacy
+            prop_name == "Source" || prop_name == "ScriptGuid" || prop_name == "RunContext"
+        }
+        "LocalScript" | "ModuleScript" => {
             // These properties shouldn't be set by scripts that are created via
             // `$path` or via being on the file system.
             prop_name == "Source" || prop_name == "ScriptGuid"