Enumerate parameters until TX Power entry is found, match
requested mW against TEXT_SELECT options, and write the
selected option index.
Added:
- str_contains_ci() for case-insensitive substring matching
- is_power_param() to detect power-related parameters
- match_power_option() to find mW in option strings
- 4 new tests: null port, frame roundtrip, success, not found
portersky
97c83aa460