Progressive quality: play-frequency prioritized generation

[rancur]

Problem

Not all 5,000 tracks deserve the same quality investment. Some tracks get played weekly, others haven't been played in years.

Proposal

Implement a play-frequency-based quality tier system:

Tier	Criteria	Quality	Cost/Track	Track Count
Hero	Played 10+/month	Kling v1.5 Pro 1080p	$15	~200
Standard	Played 1-9/month	Wan 720p + hybrid	$2.50	~1,300
Background	Played <1/month	FFmpeg motion only	$0.20	~3,500

Total: 200x$15 + 1,300x$2.50 + 3,500x$0.20 = $3,000 + $3,250 + $700 = $6,950

Implementation

1. Pull play history from Lexicon DJ API (already integrated)
2. Classify tracks into tiers based on play frequency
3. Queue generation in tier order (heroes first)
4. Allow manual tier override for specific tracks
5. Auto-upgrade: when a "background" track gets played frequently, queue re-generation at higher quality

Files to Modify

• src/lexicon.py -- add play history query
• src/bulk_processor.py -- tier-based queue ordering
• src/generator/quality_profiles.py -- add "background" profile (FFmpeg-only)
• src/pipeline.py -- respect tier in generation path

Labels: cost-optimization, feature