feat: add manifest app preflight

[anupamchugh]

Summary

• add a --manifest JSON workflow for app/device pairs
• install, verify bundle/display identity, and launch each app before streaming
• include label/bundleId in JSON output and add manifest parser tests

Test

• npx --yes bun@latest test packages/serve-sim/src/tests/manifest.test.ts packages/serve-sim/src/tests/middleware-selection.test.ts packages/serve-sim/src/tests/multi-device.test.ts
• npx --yes bun@latest run --filter serve-sim build

Notes

This is the small upstreamable piece from the simulator isolation work: it prevents stale-app confusion by verifying the source .app and installed simulator app identity before the stream starts. It leaves lane locking/dashboard behavior out of scope for this PR.