feat(editor): Add Jupyter Notebook (.ipynb) support

[akshit-sr]

feat(editor): add Jupyter Notebook (.ipynb) support

What

Adds interactive .ipynb support to the Terax editor, including notebook rendering, cell editing, Python execution, rich output rendering, and Jupyter-style keyboard shortcuts.

Why

Terax currently treats notebooks like ordinary files, which blocks common data-science and learning workflows. This lets users open, edit, run, and save Jupyter notebooks without leaving the app.

How

Added a dedicated notebook editor path for .ipynb files:

• EditorStack routes notebook files to NotebookPane.
• NotebookPane owns notebook parsing, dirty-state updates, cell operations, run-all, clear-output, and command/edit mode shortcuts.
• NotebookCell renders each cell with CodeMirror editing, markdown preview, toolbar actions, and inline autocomplete context from previous code cells.
• NotebookOutput renders streams, images, HTML, JSON, and plain-text outputs.
• src-tauri/src/modules/notebook/exec.rs manages a per-notebook Python kernel process and returns nbformat-style execution results.

Keyboard Shortcuts:

• Esc: command mode
• Enter: edit selected cell
• Shift+Enter: run cell and move/select next
• Ctrl+Enter: run cell and stay
• Alt+Enter: run cell and insert below
• ArrowUp / ArrowDown, K / J: select previous/next cell
• A / B: add code cell above/below
• M / Y / R: change selected cell to Markdown/Code/Raw
• D D: delete selected cell
• X: delete selected cell
• C: duplicate selected cell

Testing

Verified the main notebook flows manually:

• Opened an .ipynb file and confirmed it renders as notebook cells instead of raw JSON.

• Edited code and markdown cells, switched cell types, added, moved, duplicated, and deleted cells.

• Ran individual cells with the toolbar and keyboard shortcuts.

• Confirmed Shift+Enter runs while typing inside a cell instead of inserting a newline.

• Confirmed previous executed cells remain available to later cells in the same notebook kernel.

• Used Run All after Clear Outputs and confirmed code cells execute and outputs repopulate.

• Rendered stream output and matplotlib image output.

• Saved the notebook and confirmed serialized .ipynb content remains valid.

• pnpm exec tsc --noEmit clean

• Manual smoke-test of the affected feature

• (If you touched src-tauri/) cargo check clean

• (If UI) tested in pnpm tauri dev

Screenshots / GIFs

• Before:

• After:

Notes for reviewer

The backend uses a lightweight per-notebook Python process rather than a full Jupyter kernel protocol implementation. This keeps the feature small, but follow-up work could add kernel restart/interrupt controls, richer error output typing, and broader MIME output coverage.