Summary

• add a Save as Markdown action to note nodes
• prompt for a markdown file name and write the note text to the containing Space directory or workspace root
• cover markdown filename normalization and file writes with unit tests

Tests

• ./node_modules/.bin/vitest run tests/unit/contexts/noteNodeMarkdown.spec.ts
• ./node_modules/.bin/tsc -b tsconfig.node.json tsconfig.web.json --noEmit
• ./node_modules/.bin/oxlint src/contexts/workspace/presentation/renderer/components/NoteNode.tsx src/contexts/workspace/presentation/renderer/components/NoteNode.markdown.ts src/contexts/workspace/presentation/renderer/components/workspaceCanvas/nodeTypes.tsx tests/unit/contexts/noteNodeMarkdown.spec.ts
• ./node_modules/.bin/prettier --check src/contexts/workspace/presentation/renderer/components/NoteNode.tsx src/contexts/workspace/presentation/renderer/components/NoteNode.markdown.ts src/contexts/workspace/presentation/renderer/components/workspaceCanvas/nodeTypes.tsx src/app/renderer/styles/note-node.css src/app/renderer/i18n/locales/en.ts src/app/renderer/i18n/locales/zh-CN.ts tests/unit/contexts/noteNodeMarkdown.spec.ts