feat: add Cursor integration

[PipDscvr]

Summary

• add source-only Cursor integration with .cursor/mcp.json and .cursor/rules/atomicmemory.mdc templates
• document Cursor install/update/verify flow in the integrations README
• include Cursor package metadata in the shared plugin version bump helper and bump plugin versions to 0.1.8

Validation

• jq empty plugins/cursor/package.json plugins/cursor/.cursor/mcp.json .claude-plugin/marketplace.json plugins/claude-code/.claude-plugin/plugin.json plugins/codex/.codex-plugin/plugin.json plugins/codex/.codex-mcp.json plugins/openclaw/openclaw.plugin.json
• pnpm check:plugin-versions
• git diff --check
• pnpm typecheck
• pnpm build
• pnpm fallow:audit

Notes

• cursor-agent is not installed/on PATH locally, so Cursor CLI verification was documented but not run.