New function chains all three normalization stages:
1. Heteronym sentence rules (context-dependent pronunciation)
2. Pronunciation rules (token-level replacements)
3. Pipeline normalization (apostrophe, LLM)
This is the single entry point that both Web UI and PyQt should call
before TTS synthesis. Currently only Web UI uses it; PyQt has NO
normalization — this unlocks that capability.
Updated conversion_runner.emit_text to use the new function.
1038 tests pass.
