feat: Add .find() method to UICollection and EntityCollection

Implements name-based search for UI elements and entities:
- Exact match returns single element or None
- Wildcard patterns (prefix*, *suffix, *contains*) return list
- Recursive search for nested Frame children (UICollection only)

API:
  ui.find("player_frame")           # exact match
  ui.find("enemy*")                 # starts with
  ui.find("*_button", recursive=True)  # recursive search
  grid.entities.find("*goblin*")    # entity search

Closes #41, closes #40

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

Co-Authored-By: Claude <noreply@anthropic.com>

src/UICollection.h

@@ -32,6 +32,7 @@ public:
 	static PyObject* remove(PyUICollectionObject* self, PyObject* o);
 	static PyObject* index_method(PyUICollectionObject* self, PyObject* value);
 	static PyObject* count(PyUICollectionObject* self, PyObject* value);
+	static PyObject* find(PyUICollectionObject* self, PyObject* args, PyObject* kwds);
 	static PyMethodDef methods[];
 	static PyObject* repr(PyUICollectionObject* self);
     static int init(PyUICollectionObject* self, PyObject* args, PyObject* kwds);