feat(kno-14717): add trigger guide step support

[emisilvacab]

Description

Adds trigger guide step support in the cli:

• Added in_app_guide to ChannelType, STEP_TAGS and StepTagChoices
• Extended ChannelStepData with optional channel_type, guide_key, and optional template (guide steps are template-less)
• In-app guide channel steps show Guide: {guide_key} instead of channel destination lines
• Added scaffoldInAppGuideChannelStep producing the output in the screenshot
• Supports --steps in_app_guide and legacy alias in-app-guide
• Always available in getAvailableStepTypes (no channel destination required)
• Template workflow generation skips channel reference swapping for guide steps

Tasks

KNO-14717

Screenshots

Created a workflow with an in_app_guide step

Then I manually updated the <GUIDE KEY> inside workflow.json to an existing guide key, validated and pushed the workflow

[linear-code]

KNO-14717