docs(gallery): derive the gallery from the notebook sources (#746)

The Gallery page duplicated the per-notebook cards that also live in the
notebooks submodule's section index pages, and the two lists drifted across
repos: a notebook added to the submodule but not carded in gallery.md was
silently missing from the gallery (e.g. 'Interactive region annotation').

Include the section card blocks from the submodule (scverse/spatialdata-plot-notebooks#11
added the markers and root-relative paths) instead of maintaining a second
copy, and bump the submodule pin. gallery.html now renders these exact tiles
from a single source, so a newly added notebook appears automatically and the
gallery can never fall out of sync. Removes the now-orphaned _static/gallery
images (the section cards use _static/img).

Fixes #746.

Author: timtreis

docs/_static/gallery/color_and_palette.png

@@ -10,69 +10,22 @@ against the latest `spatialdata-plot` release.
 
 ## Tutorials
 
-Entry-point material for learning the API on synthetic data.
+Learn the API on synthetic data. Start with *Getting started*.
 
-::::{grid} 1 2 2 2
-:gutter: 3
-
-:::{grid-item-card} Getting started
-:link: notebooks/tutorials/getting_started
-:link-type: doc
-:img-top: _static/gallery/getting_started.png
-
-The fluent `.pl` API, layering, and styling on the in-memory `blobs`
-dataset. Ideal first read.
-:::
-
-:::{grid-item-card} Colour and palettes
-:link: notebooks/tutorials/color_and_palette
-:link-type: doc
-:img-top: _static/gallery/color_and_palette.png
-
-How `color=` resolves, the v0.3.0 `groups` behaviour, and building
-perceptually well-spaced or colourblind-safe palettes with
-`make_palette` and `make_palette_from_data`.
-:::
-
-:::{grid-item-card} Speeding up rendering
-:link: notebooks/tutorials/performance
-:link-type: doc
-:img-top: _static/gallery/performance.png
-
-Keep rendering fast on large data: automatic rasterization and scale
-selection for images, and the `datashader` backend for large collections
-of shapes and points.
+:::{include} notebooks/tutorials/index.md
+:start-after: <!-- gallery-cards-start -->
+:end-before: <!-- gallery-cards-end -->
 :::
 
-::::
-
 ## Examples
 
-Worked examples on real datasets you'd actually analyse.
-
-::::{grid} 1 2 2 2
-:gutter: 3
+Apply the API to real datasets you'd actually analyse.
 
-:::{grid-item-card} Visium mouse brain
-:link: notebooks/examples/visium_mouse_brain
-:link-type: doc
-:img-top: _static/gallery/visium_mouse_brain.png
-
-Render H&E tissue, overlay spots, color by gene expression and by cluster,
-and finish with a publication-style figure.
+:::{include} notebooks/examples/index.md
+:start-after: <!-- gallery-cards-start -->
+:end-before: <!-- gallery-cards-end -->
 :::
 
-:::{grid-item-card} Interactive region annotation
-:link: notebooks/examples/interactive_annotate
-:link-type: doc
-:img-top: _static/gallery/interactive_annotate.png
-
-Draw regions of interest directly on a `spatialdata-plot` canvas with
-`sdata.pl.annotate(...)` and persist them as a `ShapesModel` element.
-:::
-
-::::
-
 ```{toctree}
 :hidden:
 :maxdepth: 2