FIXES: Parameter-only tags like [seed:4|exag:1.0] were incorrectly using aliased narrator voice (David) instead of main narrator voice (Tony)
CAUSE: When parsing parameter-only tags, the character parser:
1. Defaulted character to 'narrator'
2. Detected segment_parameters exist
3. But only skipped alias resolution for language-only tags like [de:] or [it:]
4. Result: 'narrator' was normalized through alias system to 'david_attenborough cc3'
SOLUTION: Also skip alias resolution for parameter-only tags by detecting:
- raw_character == default_character (narrator)
- segment_parameters exist (has parameters)
- explicit_language is None (no language specification)
This ensures parameter-only tags use the main narrator voice (Tony from opt_narrator) not the aliased narrator (David)