Hack Day: Algorithmic Order Manager with DSL + Hot Swap

## Summary
Introduce an advanced order manager with algorithmic fill policy definitions, hot-swappable execution logic, and runtime observability.

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

## Graph Intent
`canonical candidate`

## Scope
- Define execution-policy DSL (versioned).
- Add runtime policy loading + hot-swap guardrails.
- Add policy outcome telemetry and explainability fields.

## Acceptance Criteria
- Multiple policies can be defined and switched without service restart.
- Fill behavior is traceable from policy input to outcome.
- Existing order lifecycle semantics remain valid.

## Decision Gate (Promote/Park)
Promote if policy-driven execution is stable, debuggable, and clearly improves extensibility over hardcoded matcher logic.

Start with the `009-order-management-matcher` state to understand the existing matcher and order lifecycle semantics. Use the acceptance criteria to define completion: policies can be switched without restart, outcomes are traceable from input to result, and existing lifecycle behavior remains valid.

Written by the indexing model from the issue text.