feat: Add 540p test config and comprehensive quality comparison

**New 540p Test Configuration:**
- config_540p_12fps.yaml (960x540, 12fps, 24 samples)
- Target: 9-10 minute render time for 30s video
- 2.25x more pixels than 360p, 9x more than 180p

**Resolution Quality Comparison Report:**
- Comprehensive analysis of 180p vs 360p vs 540p
- Visual quality assessment with frame-by-frame comparison
- Performance metrics (render time, file size, scaling)
- Decision matrix for different use cases
- Workflow recommendations

**Key Findings:**
- 360p @ 12fps is the sweet spot (6 min, good quality)
- Render time scales sub-linearly with pixels (efficient)
- Clear quality improvements at each tier
- Text readability threshold: 360p minimum
- Mascot detail threshold: 360p minimum

**Test Results:**
- 180p: 4 min, 489 KB (development only)
- 360p: 6 min, 806 KB (preview/iteration) ⭐ Recommended
- 540p: 9 min, 1.2 MB (high-quality preview)

**Validated Workflow:**
1. Develop at 360p (best quality/time ratio)
2. Preview at 540p (if client needs high quality)
3. Produce at 1080p (final output only)

Report demonstrates progressive quality scaling works as designed.

Author: claude