fix(api): expose actual PII confidence scores instead of hardcoded 0.9

[yossiovadia]

Summary

This PR fixes the PII API endpoint to return actual confidence scores from the LoRA model instead of hardcoded 0.9 values.

Fixes #717

Changes

1. Added ClassifyPIIWithDetails() method - New classifier method that returns full entity details including actual confidence scores
2. Updated DetectPII() service - Modified to use ClassifyPIIWithDetails() instead of ClassifyPII() to access real confidence values
3. Updated config.e2e.yaml - Configured to use LoRA PII model and added default catch-all decision for E2E testing

Before vs After

Before (Hardcoded)

{
  "entities": [
    {"type": "B-EMAIL_ADDRESS", "confidence": 0.9},
    {"type": "B-PERSON", "confidence": 0.9}
  ]
}

After (Actual Scores)

{
  "entities": [
    {"type": "B-EMAIL_ADDRESS", "confidence": 0.9869},
    {"type": "B-PERSON", "confidence": 0.9991}
  ]
}

Test Results

Local testing shows the API now correctly returns actual model confidence scores:

Test Case	Before	After
Email detection	0.9 (hardcoded)	0.9869 (actual)
SSN detection	0.9 (hardcoded)	0.9916, 0.8326 (actual)
Multiple PII	0.9 (hardcoded)	0.7734-0.9991 range (actual)

Technical Details

The underlying LoRA PII model was already producing accurate confidence scores (fixed in #709), but the API layer was discarding them. This change passes through the actual scores to API consumers.

The new ClassifyPIIWithDetails() method returns []PIIDetection with full entity information, while maintaining backward compatibility by keeping the existing ClassifyPII() method for callers that only need entity types.

Testing

• Local testing with make run-router-e2e
• Manual API testing with curl
• Pre-commit checks passed
• DCO sign-off added

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[github-actions]

👥 vLLM Semantic Team Notification

The following members have been identified for the changed files in this PR and have been automatically assigned:

📁 config

Owners: @rootfs, @Xunzhuo
Files changed:

• config/testing/config.e2e.yaml

📁 src

Owners: @rootfs, @Xunzhuo, @wangchen615
Files changed:

• src/semantic-router/pkg/classification/classifier.go
• src/semantic-router/pkg/services/classification.go

---

🎉 Thanks for your contributions!

This comment was automatically generated based on the OWNER files in the repository.