This update improves folder context in the reader and adds structured JSON-family reading:

- Show the full folder path in the header for files opened from nested folders
- Keep the selected file's ancestor folders visible above the scrolling file sidebar
- Open JSON, JSONC, NDJSON, and JSONL files in a collapsible structured viewer
- View JSON-family fenced blocks inside Markdown with source/viewer controls
- Keep original source line numbers visible while expanding, collapsing, and reading pretty JSON rows
- Quick Look previews now support JSON-family files with bounded native previews
- `qmv /path/to/file` on macOS now cold-starts directly to the file's parent folder with that file selected
- App-level file opens now cover Markdown, Mermaid, JSON-family files, CSV/TSV tables, and folders