fix: raise enrichment max_output_tokens from 8192 to 16384
Segments ≥360s (420-540s) were hitting the output token ceiling during
enrichment, causing IncompleteJSONError and losing all enrichment metadata
(topics, setting, emotions, corrections) for exactly the longest and most
valuable audio segments. The model (gemini-3-flash-preview) supports 65K+
output tokens; 8192 was unnecessarily conservative. Billing is per token
generated, so short segments are unaffected.
Fixes: D2 from field journal validation triage.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>