docs: add harness usage examples

[cafitac]

Summary

• add docs/harness-examples.md with copy-paste wrapper, MCP, CLI, and SDK flows
• link the new examples doc from the README MCP/SDK sections
• fix the published-wrapper docs to use the working npm exec --package ... ai-crawler -- ... form for subcommands

Testing

• uv run ai-crawler mcp-config --client hermes --launcher npm
• uv run ai-crawler mcp-config --client codex --launcher npm
• uv run ai-crawler mcp-config --client claude-code --launcher npm
• npm exec --yes --package @cafitac/ai-crawler@0.1.1 ai-crawler -- mcp-config --client hermes --launcher npm
• npm exec --yes --package @cafitac/ai-crawler@0.1.1 ai-crawler -- --version
• npm exec --yes --package @cafitac/ai-crawler@0.1.1 ai-crawler -- doctor
• uv run --extra dev python - <<'PY' ... AICrawler(...).compile_url(...) ... PY
• bash scripts/check-python.sh
• bash scripts/verify-ai-harness.sh