feat: Implement Broadcast Channel

[mMikulas]

• Added CBroadcast_Channel class implementing the core logic:
  • Holds a single message that is overwritten by new writes.
  • Uses a generation counter to track message updates.
  • Implements blocking Read using Block_Current_Process until a new generation is available.
  • Implements Write that updates the message and notifies all waiting readers.
• Created CBroadcast_FS_Driver mapped to SYS:bcast.
• Updated CProcess_Resource_Manager to "allocate" and "free" broadcast channels (fixed number of channels are preallocated).
• Implementation of broadcast is inspired by pipe implementation.