Fix parallel-monitor for GA Monitor CLI

[georgeatparallel]

Summary

• update the existing parallel-monitor skill from the alpha Monitor CLI to the GA command surface
• replace removed commands and options with --frequency, trigger, events --event-group-id, cancel, and cursor-based event retrieval
• correct list, webhook, event-history, update, and installer guidance while preserving the skill's existing structure and scope
• add a focused CI contract test that checks the skill's documented Monitor commands and flags against the latest released CLI using --help

Why

The skill still targeted the pre-GA Monitor interface. Commands and options including --cadence, simulate, event-group, delete, and --lookback no longer exist in current parallel-cli releases.

This keeps the original skill intact and changes only the stale command surface and behavior that is no longer true.

A source-level review found that a few alpha-era operational assumptions remained after the command migration: update instructions were standalone-specific, frequency was conflated with event timing, list guidance assumed historical monitors were returned by default, and webhook/event wording did not match the GA response model. Those statements now follow the released CLI implementation and API contract.

The new contract test installs the latest stable parallel-web-tools release in CI, verifies only the Monitor commands and flags documented by this skill, and rejects obsolete command invocations without treating natural-language requests such as "delete this monitor" as CLI commands.

Validation

• checked every documented Monitor command and option against parallel-cli 0.7.1 help output, source, and tests
• focused Monitor CLI contract test (3 tests)
• pre-commit run --all-files
• python3 -m unittest discover -s tests (27 tests)
• pnpm typecheck
• pnpm build
• pnpm run build:archives -- --version 0.7.0 --output release-assets