fix(gh-aw): workflow_dispatch missing command input #1626

Bug

The workflows/squad.md frontmatter declares empty workflow_dispatch: with no inputs, but the agent instructions reference github.event.inputs.command for manual triggers. Manual dispatch cannot supply mode arguments.

Found by: GPT-5.4 code review on PR #1622
Severity: Medium

Fix

Add a command input to workflow_dispatch in the frontmatter:

workflow_dispatch:
  inputs:
    command:
      description: 'Squad command (e.g., cast, connect org/repo, adopt org/repo, status)'
      required: false
      default: 'cast'

Part of #1612 epic.