feat: Optimize .t42 loading and improve decoder fidelity

src/teletext/models.py

@@ -65,9 +65,13 @@ class Page:
     Can have multiple subpages.
     """
     magazine: int
-    page_number: int  # 00-99
-    sub_code: int = 0 # Subpage code (0000 to 3F7F hex usually, simplest is 0-99 equivalent)
-    language: int = 0 # National Option (0-7)
+    page_number: int  # 00-99 (Hex storage: 0x00-0xFF)
+    sub_code: int = 0 # 13-bit subcode (0000 to 3F7F hex)
+    
+    # Control bits C4-C14
+    control_bits: int = 0 
+    
+    language: int = 0 # National Option (0-7, from C12-C14)
     packets: List[Packet] = field(default_factory=list)
     
     @property
@@ -75,6 +79,20 @@ class Page:
         # Format as Hex to support A-F pages
         return f"{self.magazine}{self.page_number:02X}"
 
+    def get_control_bit(self, n: int) -> bool:
+        """ Returns value of control bit Cn (4-14) """
+        if 4 <= n <= 14:
+            return bool((self.control_bits >> (n - 4)) & 1)
+        return False
+
+    def set_control_bit(self, n: int, value: bool):
+        """ Sets value of control bit Cn (4-14) """
+        if 4 <= n <= 14:
+            if value:
+                self.control_bits |= (1 << (n - 4))
+            else:
+                self.control_bits &= ~(1 << (n - 4))
+
     def calculate_crc(self) -> int:
         """
         Calculates the CRC-16 checksum for the page.