Restart healthy launcher when configuration changes

[leafwithered]

What changed

• Persist a fingerprint of the launcher configuration after the agent starts successfully.
• Require both a healthy agent and a matching fingerprint before taking the warm-start fast path.
• Restart the managed agent when its binary path, bind address, auth endpoints, autospin URL, local mode, or plugin version changes.
• Apply the fix consistently to the root, rendered Monk plugin, and Antigravity launcher copies.
• Add Windows and POSIX regression tests and run them in the install E2E workflow.

Why

The launchers previously treated a successful health response as sufficient proof that the running process matched the requested configuration. A healthy process started with stale auth or server settings therefore prevented the new configuration from taking effect.

Fixes #21.

Impact

Users can change launcher configuration without manually finding and killing an otherwise healthy monk-agent process. Unchanged healthy launches retain the existing fast path.

Root cause

The warm-start decision checked process health only. No durable representation of the effective configuration was recorded or compared on subsequent launches.

Validation

• Windows configuration-change regression passed locally.
• All three PowerShell launcher copies parse successfully.
• All three POSIX launcher copies pass sh -n.
• Distributed launcher copies have identical hashes.
• git diff --check passes.
• Windows and POSIX regression tests are wired into the repository's existing install E2E workflow.

The POSIX runtime regression is left to the Linux/macOS CI jobs because WSL is not available on the local Windows test host.