Add caching layer for video analysis results

[clencyc]

Description

Analyzing the same video multiple times hits the Gemini API repeatedly and costs money. Implement Redis caching for analysis results.

Acceptance Criteria

• Cache video analysis results by file hash (MD5)
• Cache TTL: 7 days by default, configurable
• Bypass cache with query param: ?skip_cache=true
• Return cache hit status in response headers
• Monitor cache hit/miss ratio
• Clear cache command available
• Redis integration tested
• Saves API costs measurably

Implementation Details

• Use Redis hash key: liveedit:analysis:{file_hash}
• Store: analysis result + timestamp
• Check cache in /api/analyze-video endpoint before calling Gemini
• Add cache metrics endpoint: GET /api/cache/stats

Configuration

• Add to .env: CACHE_TTL=604800 (7 days in seconds)
• Add to .env: ENABLE_ANALYSIS_CACHE=true

Difficulty: Medium

Estimated time: 3-4 hours