Enhance script handling and temp ID resolution in ServeSession and Reconciler

- Improved error handling in ServeSession by rolling back temp IDs if encoding fails for new scripts.
- Added logic in applyPatch to remap echoed additions from the DescendantAdded handler, preventing duplicate instances.
- Updated API to resolve intermediate container temp IDs to real tree references, ensuring proper parent-child relationships for new scripts.
- Introduced new tests to verify the presence of server info flags and the resolution of temp IDs in scripts-only mode.

These changes aim to optimize script management and enhance the overall functionality of the session handling.

tests/tests/scripts_only_pruning.rs

@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 
-use librojo::web_api::{InstanceUpdate, WriteRequest};
+use librojo::web_api::{AddedInstance, InstanceUpdate, WriteRequest};
+use rbx_dom_weak::types::{Ref, Variant};
 
 use crate::rojo_test::serve_util::run_serve_test;
 
@@ -121,7 +122,7 @@ fn scripts_only_serverinfo_flag() {
 }
 
 #[test]
-fn scripts_only_serverinfo_flag_absent_when_disabled() {
+fn scripts_only_serverinfo_flag_present_for_other_fixture() {
     run_serve_test("syncback_scripts_only", |session, _redactions| {
         let info = session.get_api_rojo().unwrap();
         assert!(
@@ -131,6 +132,17 @@ fn scripts_only_serverinfo_flag_absent_when_disabled() {
     });
 }
 
+#[test]
+fn scripts_only_serverinfo_flag_false_when_disabled() {
+    run_serve_test("empty", |session, _redactions| {
+        let info = session.get_api_rojo().unwrap();
+        assert!(
+            !info.sync_scripts_only,
+            "syncScriptsOnly should default to false when not set in project"
+        );
+    });
+}
+
 #[test]
 fn scripts_only_write_filters_non_script_updates() {
     run_serve_test("scripts_only_read_pruning", |session, _redactions| {
@@ -278,3 +290,82 @@ fn scripts_only_websocket_injects_ancestors_for_new_script() {
         );
     });
 }
+
+#[test]
+fn scripts_only_write_resolves_intermediate_temp_ids() {
+    run_serve_test("scripts_only_read_pruning", |session, _redactions| {
+        let info = session.get_api_rojo().unwrap();
+        let root_id = info.root_instance_id;
+        let read_response = session.get_api_read(root_id).unwrap();
+
+        let sss_id = read_response
+            .instances
+            .iter()
+            .find(|(_, inst)| inst.class_name == "ServerScriptService")
+            .map(|(id, _)| *id)
+            .expect("ServerScriptService should exist");
+
+        // PureParts exists on disk but is pruned from the read response.
+        // Simulate the DescendantAdded handler: send PureParts as an
+        // intermediate container with a temp ID, and a new script under it.
+        let temp_folder_ref = Ref::new();
+        let temp_script_ref = Ref::new();
+
+        let folder_added = AddedInstance {
+            parent: Some(sss_id),
+            name: "PureParts".to_string(),
+            class_name: "Folder".to_string(),
+            properties: HashMap::new(),
+            children: vec![],
+        };
+
+        let mut script_props = HashMap::new();
+        script_props.insert(
+            "Source".to_string(),
+            Variant::String("return 'temp id test'".to_string()),
+        );
+        let script_added = AddedInstance {
+            parent: Some(temp_folder_ref),
+            name: "TempIdScript".to_string(),
+            class_name: "ModuleScript".to_string(),
+            properties: script_props,
+            children: vec![],
+        };
+
+        let mut added_map = HashMap::new();
+        added_map.insert(temp_folder_ref, folder_added);
+        added_map.insert(temp_script_ref, script_added);
+
+        let write_request = WriteRequest {
+            session_id: info.session_id,
+            removed: vec![],
+            added: added_map,
+            updated: vec![],
+            stage_ids: Vec::new(),
+        };
+
+        session
+            .post_api_write(&write_request)
+            .expect("Write request should succeed");
+
+        std::thread::sleep(std::time::Duration::from_millis(500));
+
+        let read_after = session.get_api_read(root_id).unwrap();
+        let names: Vec<&str> = read_after
+            .instances
+            .values()
+            .map(|inst| inst.name.as_ref())
+            .collect();
+
+        assert!(
+            names.contains(&"TempIdScript"),
+            "TempIdScript should appear after temp ID resolution. Got: {:?}",
+            names
+        );
+        assert!(
+            names.contains(&"PureParts"),
+            "PureParts should now be included (has script descendant). Got: {:?}",
+            names
+        );
+    });
+}