Add SettingsTab, StatusTab, DataTab and wire up DeviceController

- SettingsTab: chamber ID, master CSV mapping (families A-Z), wafer
  behavior toggle, light/dark mode toggle, Edit CSV Metadata dialog
- StatusTab: connection status card, wafer info, activity log (blank
  until Detect Wafer fires from the side rail)
- DataTab: empty state, ready for parsed data
- HomePage: side rail buttons dispatch device actions and jump to
  Status tab; selectedSideActionIndex defaults to -1 on startup
- DeviceController registered as QML context property in main.py
- LocalSettings: added status persistence fields
- Theme: added subheadingColor and disabledText
- Added serialcomm/ package and backend data/graph modules
- gitignore: restore clean version

backend/csv_file_metadata.py

@@ -4,11 +4,12 @@ from datetime import datetime
 # ===== CSV Metadata Model =====
 class CSVFileMetadata:
     # ===== Lifecycle =====
-    def __init__(self, wafer="", date="", chamber="", notes="", filename="", columns=0):
+    def __init__(self, wafer="", date="", chamber="", notes="", master_type="", filename="", columns=0):
         self.wafer = wafer
         self.date = date
         self.chamber = chamber
         self.notes = notes
+        self.master_type = master_type
 
         self.filename = filename
         self.columns = columns
@@ -42,6 +43,7 @@ class CSVFileMetadata:
             "date": self.string_date_format(),  # Ensure we save as string
             "chamber": self.chamber,
             "notes": self.notes,
+            "masterType": self.master_type,
         }
 
     def string_date_format(self) -> str: