feat: offer agent migration during install.sh and hermes setup

[teknium1]

Problem

Users switching from OpenClaw (or other agents) need their config, API keys, platform tokens, etc. migrated to Hermes. Currently this lives as an optional skill that requires a running agent — chicken-and-egg problem since migration brings over the keys needed to run the agent.

The previous proposal (#826) suggested a hermes migrate CLI subcommand, but that still requires Hermes to be installed first.

Proposal

Integrate migration detection into the existing install/setup flows so it happens naturally:

1. install.sh — post-install detection

After installing Hermes, the install script checks for known agent configs:

# At the end of install.sh, after successful install:
if [ -d "$HOME/.openclaw" ]; then
    echo ""
    echo "Detected OpenClaw installation at ~/.openclaw/"
    echo "Would you like to import your settings (API keys, platform configs, memories)?"
    read -p "Import from OpenClaw? [Y/n] " reply
    if [ "$reply" != "n" ] && [ "$reply" != "N" ]; then
        hermes setup --migrate-from openclaw
    fi
fi

Could also detect ~/.claude/, ~/.codex/ etc. for future migration paths.

2. hermes setup — interactive migration step

At the beginning of the setup wizard (before asking for API keys), auto-detect and offer migration:

# In hermes_cli/setup.py, at the start of run_setup_wizard():
from pathlib import Path

openclaw_dir = Path.home() / ".openclaw"
if openclaw_dir.exists():
    print("Detected OpenClaw installation at ~/.openclaw/")
    print("Hermes can import your API keys, platform configs, memories, and skills.")
    reply = input("Import from OpenClaw? [Y/n] ").strip().lower()
    if reply in ('', 'y', 'yes'):
        _run_openclaw_migration()
        print("Migration complete! Continuing with setup...")
        # Skip API key prompts if they were imported

Add a --migrate-from flag to hermes setup so install.sh can trigger it directly:

hermes setup --migrate-from openclaw

3. Migration logic

Reuse the existing migration script at optional-skills/migration/openclaw-migration/scripts/openclaw_to_hermes.py. It already handles 19 categories (API keys, platform tokens, model config, TTS, memories, skills, etc.) with 24 tests.

The setup integration should:

• Run the migration with sensible defaults (no preset selection needed — just import everything)
• Show a summary of what was imported
• Skip API key / platform setup prompts for anything that was successfully migrated
• Still allow the user to override/change imported values during the rest of setup

Benefits

• Zero friction: migration happens naturally during first install
• No chicken-and-egg: no API keys needed to run the migration
• Extensible: easy to add detection for other agents (~/.claude/, ~/.codex/, etc.)
• The existing migration script does all the heavy lifting — this is just a wrapper

Supersedes #826.