Phase 2: Rule management, streaming parsing & enterprise features for HAR redaction

[pillowbytes]

Phase 2: Rule management, streaming parsing & enterprise features for HAR redaction

Follow-up to #31

Goal
Add rule import/export, policy presets, streaming parsing for very large HAR files, and audit UI for enterprise customers.

Acceptance criteria

• Import/export rule JSON for company policies.
• Serverless/streaming parsing strategy for HARs >100MB.
• Audit UI for applied redactions with downloadable manifests.

Notes
This is an enterprise-focused phase and requires careful testing and performance optimization.