Add P25 NAC alias support for streaming

[msullivan1993]

Adds P25 NAC (Network Access Code) alias support, allowing users to create aliases based on NAC values for streaming and identification. Tested with P25 conventional channels streaming to Rdio Scanner with correct talkgroup override.

• Added NAC as an alias identifier type
• NAC values (0-4095) can be configured in the alias editor under P25 → NAC
• Streaming works correctly with "Stream this Alias as Talkgroup" setting
• Fixed RdioScannerBroadcaster to check all identifiers for StreamAsTalkgroup, not just the TO identifier

Files Changed

• NEW: alias/id/nac/Nac.java
• NEW: gui/playlist/alias/identifier/NacEditor.java
• Modified: 7 existing files (see commit)

Tested with Rdio scanner, unknown if any changes are needed for Calls, OpenMHz, etc. Again, I am no coder, Claude Opus did the bulk of the work.