Remove deprecated 'daf upgrade' command

[itdove]

Overview

Remove the deprecated daf upgrade command that has been replaced by daf skills.

Context

The daf upgrade command was deprecated in favor of the new daf skills command which provides:

• Better command naming that reflects actual functionality
• Specific skill installation support (daf skills skill_name)
• Clear install/upgrade/uninstall operations
• Consistent multi-agent support

Tasks

• Remove upgrade command from devflow/cli/main.py
• Update any remaining documentation references
• Update CHANGELOG with breaking change notice
• Verify no internal code depends on this command

Migration Guide for Users

Old command:

daf upgrade
daf upgrade --agent cursor
daf upgrade --all-agents

New command:

daf skills
daf skills --agent cursor
daf skills --all-agents

Timeline

Target removal: Version 3.0

References

• Issue Add multi-agent skill installation with directory mapping (global + project-level) #288: Multi-agent skill installation implementation
• PR implementing deprecation warning