Fix help message to use correct personality package path

[Copilot]

The help message example used an incomplete personality reference personalities.assistant instead of the full package path required by the implementation.

Changes

• Updated help message in __main__.py line 74 to use seclab_taskflow_agent.personalities.assistant

This aligns with:

• README.md documentation (line 71)
• available_tools.py implementation that expects format "packagename.filename"
• All taskflow YAML files in the codebase

# Before
help_msg += "`-p personalities.assistant explain modems to me please`\n"

# After
help_msg += "`-p seclab_taskflow_agent.personalities.assistant explain modems to me please`\n"

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.