fix: make duplication scoring more strict and lower LSH threshold

## Problems Fixed

1. **Duplication scoring too lenient**: 5.8% duplication was scored as
   100/100 (perfect) because thresholds were too high
2. **LSH threshold preventing clone detection**: 0.78 threshold filtered
   too many candidates, reducing detection accuracy

## Changes

### Duplication Scoring Thresholds (domain/analyze.go)
- `DuplicationThresholdLow`: 10.0 → 3.0
- `DuplicationThresholdMedium`: 25.0 → 10.0
- `DuplicationThresholdHigh`: 40.0 → 20.0

New scoring behavior:
- 0-3% duplication → score 100 (excellent)
- 3-10% duplication → score 70 (good, needs attention)
- 10-20% duplication → score 40 (poor)
- >20% duplication → score 0 (critical)

### LSH Threshold (.pyscn.toml)
- `lsh_similarity_threshold`: 0.78 → 0.50
- Lower threshold allows more clone candidates for APTED verification
- Improves recall without significantly impacting precision

## Impact

Before: `Duplication: 100/100 ✅ (5.8% duplication, 5 groups)`
After: `Duplication: 70/100 👍 (5.8% duplication, 5 groups)`

The score now accurately reflects that 5.8% duplication with 5 clone
groups requires attention, while still maintaining an overall healthy
codebase grade.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.pyscn.toml

@@ -76,7 +76,7 @@ k_core_k = 2                     # K-core parameter
 # LSH acceleration settings
 lsh_enabled = "auto"             # Enable LSH: true, false, auto (based on project size)
 lsh_auto_threshold = 500         # Auto-enable LSH for projects with >500 fragments
-lsh_similarity_threshold = 0.78  # LSH similarity threshold
+lsh_similarity_threshold = 0.50  # LSH similarity threshold
 lsh_bands = 32                   # Number of LSH bands
 lsh_rows = 4                     # Number of rows per band
 lsh_hashes = 128                 # Number of hash functions

domain/analyze.go

@@ -17,9 +17,9 @@ const (
 	ComplexityPenaltyLow      = 6
 
 	// Code duplication thresholds and penalties
-	DuplicationThresholdHigh   = 40.0
-	DuplicationThresholdMedium = 25.0
-	DuplicationThresholdLow    = 10.0
+	DuplicationThresholdHigh   = 20.0
+	DuplicationThresholdMedium = 10.0
+	DuplicationThresholdLow    = 3.0
 	DuplicationPenaltyHigh     = 20
 	DuplicationPenaltyMedium   = 12
 	DuplicationPenaltyLow      = 6