fix: verify launchd server startup after install

[git-ksk]

Summary

• Briefly verify a freshly bootstrapped launch agent instead of treating launchctl bootstrap success as server startup success.
• Check launchd state before probing the configured TCP endpoint.
• Fail fast on immediate exit status or terminating signal and point directly to server.error.log.
• Keep verification bounded to 1 second; a still-running process is accepted without a long install-time wait.

Reproduction

A temporary LaunchAgent whose program exits immediately with status 78 reproduces the false positive: launchctl bootstrap returns 0, while launchctl print shortly afterward reports state = not running and last exit code = 78: EX_CONFIG.

A signal-terminated job is reported separately by launchd as last terminating signal = Terminated: 15, so startup acceptance needs to handle both forms.

Root cause

install previously checked only the return code from launchctl bootstrap. Bootstrap confirms that launchd accepted the job definition; it does not guarantee that the server process remained alive or reached its listen endpoint.

Validation

• focused launchd tests: 7 passed
• full suite: 326 passed
• physical acceptance with isolated temporary LaunchAgents rejects both EX_CONFIG 78 and SIGTERM 15
• the production com.macos-mcp.server LaunchAgent was not modified during failure-path acceptance
• git diff --check: clean
• no added line exceeds the repository's 100-character limit
• ruff check .: 461 findings vs 462 on upstream/main (no new findings)
• ruff format --check .: same 26 pre-existing unformatted files as upstream/main; the new test file is formatted

Non-changes

• no changes to launchd identity or plist semantics
• no TCC database changes
• no signing/notarization changes or Issue Feature request: ship a code-signed + notarized release so TCC attributes access to one named entity #25 work
• no long startup wait

[git-ksk]

Closing temporarily for a final pre-PR repository-guideline review. The branch is preserved; this will only be reopened after the final scope/style/test review is complete.

[git-ksk]

Superseded by #63. The fork branch was amended after the contribution-guideline audit, and GitHub does not allow reopening this PR after that force-push.