chore: gitignore trials/ scratchpad directory

Author: GLips

.gitignore

@@ -43,4 +43,7 @@ Thumbs.db
 
 # Private planning / brainstorm / ideas workspace — version-controlled in a
 # separate private repo (FramelinkAI/mcp-docs) cloned to this path.
-/docs/
+/docs/
+
+# Local experiment scratchpad
+/trials/