Move performance notebook from examples to tutorials

It teaches rendering performance end-to-end on a real dataset, so it fits
Tutorials rather than the single-feature Examples gallery. Moves the gallery
card and toctree entry accordingly.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: timtreis

examples/index.md

@@ -23,16 +23,6 @@ Draw regions of interest directly on a `spatialdata-plot` canvas with
 `sdata.pl.annotate(...)` and persist them as a `ShapesModel` element.
 :::
 
-:::{grid-item-card} Speeding up rendering
-:link: performance
-:link-type: doc
-:img-top: ../_static/img/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.
-:::
-
 ::::
 
 ```{toctree}
@@ -41,5 +31,4 @@ of shapes and points.
 
 visium_mouse_brain
 interactive_annotate
-performance
 ```

tutorials/index.md

@@ -24,6 +24,16 @@ perceptually well-spaced or colourblind-safe palettes with
 `make_palette` and `make_palette_from_data`.
 :::
 
+:::{grid-item-card} Speeding up rendering
+:link: performance
+:link-type: doc
+:img-top: ../_static/img/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.
+:::
+
 ::::
 
 ```{toctree}
@@ -32,4 +42,5 @@ perceptually well-spaced or colourblind-safe palettes with
 
 getting_started
 color_and_palette
+performance
 ```