Support full dynamic scalability - NUM_ZONES (1-48)

[komal-SkyNET]

Summary

Updates the firmware to support 8 irrigation zones by default (previously 4), with full dynamic scalability from
1-48 zones.

Changes

• Increased NUM_ZONES from 4 to 8 zones
• Made code fully dynamic: Simply change NUM_ZONES constant and everything adapts automatically
  • Generated 48 callback functions (Hunter controller max)
  • Dynamic zone naming and Zigbee endpoint allocation
  • Loop-based callback attachment
• Added compile-time safety checks: Prevents invalid NUM_ZONES values (must be 1-48)
• Improved code readability: Added clear comments for configuration
• Fixed pre-existing bug: Corrected malformed comment in HunterRoam.cpp

Technical Details

• Zone names: Dynamically generated ("Zone 1", "Zone 2", ...)
• Endpoints: Auto-assigned sequentially (10, 11, 12, ...)
• Memory usage: 9.1% RAM, 40.9% Flash (plenty of headroom)
• All array accesses are bounds-safe

Documentation

• Updated README.md to reflect 8-zone default
• Added inline comments explaining dynamic configuration