refactor: add types to project.py

cells.py

@@ -0,0 +1,28 @@
+import os
+from typing import List, Dict, TypedDict, Optional
+import json
+
+class Port(TypedDict):
+    kind: str
+    name: str
+    direction: str
+    description: str
+
+class Cell(TypedDict):
+    description: str
+    file_prefix: str
+    library: str
+    name: str
+    parameters: List[str]
+    ports: List[Port]
+    type: str
+    verilog_name: str
+    equation: Optional[str]
+
+Cells = Dict[str, Cell]
+
+def load_cells() -> Cells:
+   script_dir = os.path.dirname(os.path.realpath(__file__))
+   with open(os.path.join(script_dir, 'cells.json')) as fh:
+     return json.load(fh)
+