Hack Day: Visual DSL Editor + Execution Visualizer

## Summary
Add a visual editor and runtime visualizer for order execution DSL rules and observed behavior.

## Jump-Off State(s)
- `009-order-management-matcher`

## Graph Intent
`optional branch` (possible canonical follow-on)

## Scope
- Build rule graph/tree editor for DSL authoring.
- Visualize real-time execution path for submitted orders.
- Add policy version diff + rollback UX.

## Acceptance Criteria
- Users can author/validate DSL policies via UI.
- Runtime views show which rule path produced fill outcomes.
- Editor output is deterministic and validates before activation.

## Decision Gate (Promote/Park)
Promote if it materially improves learning/demo value and operator safety for policy changes.

Start by reading the `009-order-management-matcher` state and tracing how DSL policies and submitted orders are represented. Done means a UI can author and validate deterministic policies, show the rule path behind fill outcomes, and support policy version diff and rollback before activation.

Written by the indexing model from the issue text.