feat(agent-test): run managed runtimes through Town

Description

The pitch.

## Problem

A prepared runtime still needs lifecycle-safe orchestration through the shared loopback adapter and Town evaluator without coupling the engine to OpenClaw internals.

## Change

- bridge a prepared runtime into the shared local adapter server
- drive the resulting participant through the real Town test engine
- preserve runtime-owned display, target, issue policy, and sanitized attribution
- own replay, worker shutdown, cancellation, and cleanup ordering

## Verification

- final stack: `make ci-local` — all 5 checks passed; 2,081 passed, 2 skipped, 1 deselected
- managed lifecycle, replay, cancellation, cleanup, sanitization, and unchanged engine regressions pass
- synthetic connector coverage proves the bridge itself is connector-neutral
- independent final stacked-tail review: READY, no Critical or Important findings

## Stack

**8 of 9. Depends on PR 7.** PR 9 adds OpenClaw autodetection, CLI UX, docs, and installed-process proof.

**Merge note:** After #226 merges into `main`, retarget this PR to `main`, wait for its CI, and only then merge it.