Add AI agent quick-start section to help output

[kwent]

Summary

• Adds a "Start here (for AI agents)" section to rootly --help output
• Shows command pattern, --format=json tip, common resource commands, and discovery hints
• Inspired by Harbor CLI's agent-friendly help — gives AI agents structured guidance instead of requiring them to guess from flag docs

Test plan

• go run cmd/rootly/main.go --help shows new section
• All existing tests pass (go test ./internal/cmd/...)

[greptile-apps]

Greptile Summary

Appends an "AI agent quick-start" section to the rootly --help long description, giving agents a structured overview of the command pattern, --format=json usage, and seven concrete example commands with inline annotations.

• The seven example commands (incidents list/get, alerts list, services list, teams list, oncall who, pulse create) all correspond to real, registered subcommands verified in the codebase.
• The change is purely cosmetic/documentation — no logic, flags, or behaviour is modified.

Confidence Score: 5/5

This is a documentation-only change to the root command's help text; no logic, flags, or runtime behaviour is affected.

Every command and verb referenced in the new help text (incidents get, oncall who, pulse create, etc.) exists as a real registered subcommand. The change touches only the Long string literal and introduces no new behaviour.

No files require special attention.

Important Files Changed

Filename	Overview
internal/cmd/root.go	Adds an AI agent quick-start section to the Long help text; all referenced subcommands (incidents, alerts, services, teams, oncall, pulse) and verbs exist in the codebase.

_{Reviews (1): Last reviewed commit: "feat(help): add AI agent quick-start sec..." | Re-trigger Greptile}