feat: offer OpenClaw migration during first-time setup wizard

[teknium1]

Summary

Closes #829. When a new user runs hermes setup for the first time and ~/.openclaw/ exists, the wizard offers to import their OpenClaw data before API/tool configuration begins.

How it works

1. During first-time setup, after "Press Enter to begin" and before any config sections
2. Detects ~/.openclaw/ directory
3. Asks: "Would you like to import from OpenClaw?"
4. If accepted, dynamically loads the existing migration script from optional-skills/migration/openclaw-migration/scripts/openclaw_to_hermes.py
5. Runs with full preset, execute=True, overwrite=False
6. Prints a summary of what was imported
7. Reloads config so imported values (API keys, etc.) are available for remaining setup steps

Design decisions

• No new CLI flags or installer changes — the migration is offered naturally within the interactive setup wizard flow
• Only on first-time setup — returning users already have their config; they can use the openclaw-migration skill directly
• Reuses existing script — dynamically imports the migration script rather than duplicating logic
• Graceful failures — if migration fails for any reason, setup continues normally
• Config bootstrap — creates config.yaml before migration if it doesn't exist yet (migration script reads it)

Changes

File	Change
hermes_cli/setup.py	Added _offer_openclaw_migration() + call in first-time setup flow
tests/hermes_cli/test_setup_openclaw_migration.py	9 tests covering detection, acceptance, decline, errors, config reload

Testing

• python -m pytest tests/hermes_cli/test_setup_openclaw_migration.py -v → 9 passed
• python -m pytest tests/ -q → 3255 passed (2 pre-existing failures in unrelated test)