feat: add ag setup command

[anuragts]

Summary

Adds an ag setup command to scaffold and start a new AgentOS in one flow.

This wires a new Typer command through libs/agno_infra/agno/cli/entrypoint.py and adds setup_agentos() in libs/agno_infra/agno/infra/operator.py to:

• install missing setup packages into the active CLI environment
• create an AgentOS codebase from the selected starter template
• start the generated infrastructure with the existing infra startup path

(If applicable, issue number: #____)

Type of change

• Bug fix
• New feature
• Breaking change
• Improvement
• Model update
• Other:

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Checklist

• Code complies with style guidelines
• Ran format/validation scripts (./scripts/format.sh and ./scripts/validate.sh)
• Self-review completed
• Documentation updated (comments, docstrings)
• Examples and guides: Relevant cookbook examples have been included or updated (if applicable)
• Tested in clean environment
• Tests added/updated (if applicable)

Duplicate and AI-Generated PR Check

• I have searched existing open pull requests and confirmed that no other PR already addresses this issue
• If a similar PR exists, I have explained below why this PR is a better approach
• Check if this PR was entirely AI-generated (by Copilot, Claude Code, Cursor, etc.)

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Additional Notes

Validation run before opening this PR:

• ./scripts/format.sh: passed; no files changed
• ./scripts/validate.sh: command exited 0, libs/agno_infra ruff and mypy passed, cookbook checks passed; the run printed existing mypy errors in unrelated libs/agno files including tools/parallel.py, os/interfaces/agui/handlers.py, models/google/gemini*.py, models/aws/claude.py, and context/web/exa.py