Fix/script path assets prefix and ctx warn bug (#453)

* Fix script path handling and FastMCP Context API usage

1. Fix script path doubling when Assets prefix is used
   - ManageScript.TryResolveUnderAssets now properly handles both Assets and Assets/ prefixes
   - Previously, paths like Assets/Script.cs would create files at Assets/Assets/Script.cs
   - Now correctly strips the prefix and creates files at the intended location

2. Fix FastMCP Context API call in manage_asset
   - Changed ctx.warn() to ctx.warning() to match FastMCP Context API
   - Fixes AttributeError when manage_asset encounters property parse errors
   - Affects ScriptableObject creation and other asset operations with invalid properties

* Fix manage_asset error handling to use ctx.error

Changed ctx.warning to ctx.error for property parse errors in manage_asset
tool to properly handle error cases. This ensures parse errors are reported
as errors rather than warnings, and fixes compatibility with FastMCP Context API.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

---------

Co-authored-by: Claude Sonnet 4.5 <[email protected]>

Author: dsarno

MCPForUnity/Editor/Tools/ManageScript.cs

@@ -65,7 +65,17 @@ private static bool TryResolveUnderAssets(string relDir, out string fullPathDir,
             // Normalize caller path: allow both "Scripts/..." and "Assets/Scripts/..."
             string rel = (relDir ?? "Scripts").Replace('\\', '/').Trim();
             if (string.IsNullOrEmpty(rel)) rel = "Scripts";
-            if (rel.StartsWith("Assets/", StringComparison.OrdinalIgnoreCase)) rel = rel.Substring(7);
+
+            // Handle both "Assets" and "Assets/" prefixes
+            if (rel.Equals("Assets", StringComparison.OrdinalIgnoreCase))
+            {
+                rel = string.Empty;
+            }
+            else if (rel.StartsWith("Assets/", StringComparison.OrdinalIgnoreCase))
+            {
+                rel = rel.Substring(7);
+            }
+
             rel = rel.TrimStart('/');
 
             string targetDir = Path.Combine(assets, rel).Replace('\\', '/');

Server/src/services/tools/manage_asset.py

@@ -80,7 +80,7 @@ async def _normalize_properties(raw: dict[str, Any] | str | None) -> tuple[dict[
 
     properties, parse_error = await _normalize_properties(properties)
     if parse_error:
-        await ctx.warn(parse_error)
+        await ctx.error(parse_error)
         return {"success": False, "message": parse_error}
 
     # Coerce numeric inputs defensively