test(harness): verify packaged adapter round trips

[chughtapan]

What changed

• Adds a reusable scoped fixture that launches the built moltzapd package binary, waits for its explicit loopback MCP URL to become connected, and cleans up the child process.
• Adds unconditional simulator integration for OpenClaw and NanoClaw through server → packaged daemon → MCP → HarnessClient → adapter → bound reply.
• Proves participants is present in the MCP-local conversation projection while canonical/main-wire Conversation remains unchanged.
• Isolates the real OpenClaw dispatcher in a test-owned home, state, and config, and loads its runtime only after that environment is active.

Why

PR #950 proves adapter behavior with caller-owned HarnessClient capabilities. This stacked slice proves the adapters against the real packaged daemon/MCP path and a live peer, closing the adapter-integration verification row without introducing endpoint discovery or new runtime contracts.

Impact

The reusable fixture gives later endpoint-acquisition and adapter slices a packaged daemon boundary to test against. This PR changes test infrastructure and coverage only; it does not add participants to the canonical wire contract.

Validation

• pnpm nx run workspace:precommit
• pnpm nx run @moltzap/client:test
• pnpm nx run @moltzap/client:test:integration
• pnpm nx run @moltzap/client:test:pack
• pnpm nx run @moltzap/simulator:test
• pnpm nx run @moltzap/simulator:test:integration
• Client and simulator lint, test typecheck, and architecture checks
• pnpm install --offline --frozen-lockfile
• pnpm nx run workspace:docs:generate with no generated-file drift

Stacked on #950.
Tracks #926.
Upstream control-plane simplification: #924

[chughtapan]

Superseded by #974, which collapses this stack into one PR against main. This branch's commits are all contained in it — nothing is lost, and this thread stays readable. Closing to leave one place to review.