docs(space): add SPATA2-inspired AnnData utilities tutorial

[hurry060215-tech]

Summary

Adds rendered English and Chinese notebooks for the SPATA2-inspired AnnData spatial utilities introduced in omicverse/omicverse#847.

The tutorial is scoped as an initial AnnData helper workflow, not as full SPATA2 parity documentation.

Tutorial flow

1. Build a deterministic Visium-like AnnData fixture with a tissue grid, smooth gene-like variables, and isolated artifact spots.
2. Extract coordinate tables with ov.space.spata2_get_coords.
3. Join coordinates with observation metadata and molecular variables via ov.space.spata2_join_variables.
4. Render spatial gene-like gradients.
5. Identify and render a convex-hull tissue outline with ov.space.spata2_tissue_outline.
6. Detect isolated observations with ov.space.spata2_identify_outliers.
7. Remove flagged observations with ov.space.spata2_remove_outliers.
8. Demonstrate explicit pixel-to-unit and unit-to-pixel conversion.
9. Include a notebook-local benchmark and a parity-context section so readers do not mistake this helper layer for complete SPATA2 parity.

Changes

• Updates English navigation pages.
• Updates Chinese navigation pages.
• Adds/refreshes executed notebooks:
  • docs/Tutorials-space/t_spata2py.ipynb
  • docs_zh/Tutorials-space/t_spata2py.ipynb
• Fixes corrupted Chinese markdown in the notebook and new Chinese SPATA2 index page.
• Rewords the tutorial from "SPATA2 reconstruction/parity" to "SPATA2-inspired AnnData spatial utilities".

Validation

• Executed English notebook with PYTHONPATH=D:\scop-dev\omicverse-pr847 against the updated #847 worktree.
• Executed Chinese notebook with PYTHONPATH=D:\scop-dev\omicverse-pr847 against the updated #847 worktree.
• nbformat.validate() passed for both notebooks.
• Checked both notebooks have 26 cells and no corrupted ??? markdown text.
• git diff --check

Merge note

Merge this tutorial after omicverse/omicverse#847, because it imports the new ov.space.spata2_* APIs.