T8: Add legacy lambda wrapper to RedactionPipeline

[dpaluy]

Task Details

Priority: p2 | Story Points: 2 | Group: B (Core Infrastructure)
Depends on: T3

Files

• lib/tracebook/redaction_pipeline.rb

Acceptance Criteria

• Single-arg lambdas (legacy) work alongside new (text, audit:) interface
• Wrapper detects arity and calls appropriate signature
• Backwards compatible with existing custom_redactors

Context

Part of PII Redaction Architecture Refactor - Phase 2: Pattern System
Plan Review Fix #4: Custom redactors interface breaks LSP

See full plan: docs/plans/260106-02b-pii-redaction-architecture.md