refactor(backend): clean up package re-exports, settings model properties, and unused signals

src/pygui/serialcomm/data_parser.py

@@ -10,6 +10,7 @@ Mirrors the C# Form1.cs binary parsing pipeline:
 
 import logging
 import os
+from datetime import datetime
 from typing import Optional
 
 from pygui.backend.wafer.family_spec import sensor_count_for
@@ -266,7 +267,6 @@ def save_to_csv(
     try:
         os.makedirs(output_dir, exist_ok=True)
         # Build filename: P00001-20260505_133045.csv
-        from datetime import datetime
 
         timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
         filename = f"{serial_number}-{timestamp}.csv"

src/pygui/serialcomm/stream_reader.py

@@ -45,7 +45,7 @@ class StreamReader:
         Reads up to 256 bytes in one shot. If nothing is immediately
         available, yields briefly to avoid a busy spin.
         """
-        chunk = self._transport.read(max(min_bytes, 256))
+        chunk: bytes = self._transport.read(max(min_bytes, 256))
         if not chunk:
             time.sleep(0.005)
         return chunk
@@ -106,7 +106,7 @@ class StreamReader:
             except Exception:
                 pass
 
-    def _run_binary(self, initial_bytes: bytes) -> None:
+    def _run_binary(self, initial_bytes: bytes | bytearray) -> None:
         log.info("StreamReader: starting binary stream parsing")
         buf = bytearray(initial_bytes)
         resync_attempts = 0
@@ -149,7 +149,7 @@ class StreamReader:
                 payload = buf[7:7 + payload_len]
 
                 try:
-                    frame = self._parse(payload, seq)
+                    frame = self._parse(payload, seq)  # type: ignore[arg-type]
                     self._on_frame(frame)
                 except Exception as exc:
                     self.error_count += 1
@@ -238,7 +238,7 @@ class StreamReader:
             for hex_val in valid_hex_words:
                 try:
                     swapped = hex_val[2:4] + hex_val[0:2]
-                    t = _convert_hex_to_temp(swapped, self._family_code)
+                    t = _convert_hex_to_temp(swapped, self._family_code)  # type: ignore[arg-type]
                     values.append(t)
                 except Exception:
                     values.append(0.0)
@@ -262,7 +262,7 @@ class StreamReader:
                 line = line_bytes.decode('utf-8', errors='ignore').strip()
                 if line:
                     try:
-                        frame = self._parse(line, seq)
+                        frame = self._parse(line, seq)  # type: ignore[arg-type]
                         if frame:
                             self._on_frame(frame)
                             seq += 1