docs: list every use case in the sidebar

The three gallery pages held thirteen examples as rows in a table, reachable
only by opening the gallery first. Each is now its own page, so the sidebar
lists them and search finds them by name.

A page for an example that lives in vectordb-recipes says so and links to the
notebook and its source, rather than pretending the tutorial is here.

Overview moves above the groups -- the tab uses pages rather than groups, which
is what allows an entry to sit outside every group. Stable World Model joins
Training, since that is what it is doing. The agent plugin page is now Using
LanceDB Agent Skill.

Mintlify cannot link outward from a sidebar: an {anchor, href} entry is ignored
and a bare URL renders with its scheme mangled to a single slash, so a real page
per example is the only way to list them.

docs/web/tutorials/feature-engineering/feature-engineering-101.mdx

@@ -0,0 +1,23 @@
+---
+title: "Feature engineering 101"
+sidebarTitle: "Feature Engineering 101"
+description: "Add derived feature columns to an existing table."
+---
+
+Adds new derived features to a table, the pattern documented under
+[data evolution](/feature-engineering/data-evolution) and
+[computed columns](/feature-engineering/add-computed-column).
+
+<Note>
+This example is a runnable notebook in the
+[vectordb-recipes](https://github.com/lancedb/vectordb-recipes) repository rather than a page here.
+</Note>
+
+<CardGroup cols={2}>
+  <Card title="Open in Colab" icon="google" href="https://colab.research.google.com/github/lancedb/vectordb-recipes/blob/main/tutorials/feature-engineering/feature-engineering-101.ipynb">
+    Run it end to end in the browser.
+  </Card>
+  <Card title="View on GitHub" icon="github" href="https://github.com/lancedb/vectordb-recipes/tree/main/tutorials/feature-engineering/feature-engineering-101.ipynb">
+    Read the source.
+  </Card>
+</CardGroup>

docs/web/tutorials/feature-engineering/index.mdx

@@ -1,22 +0,0 @@
----
-title: "More feature engineering examples"
-sidebarTitle: "More Examples"
-description: "Notebooks covering derived features and materialized views."
-layout: wide
----
-
-| Example | Description |
-|--------|:------------|
-| **Feature Engineering 101** <br /> <a href="https://colab.research.google.com/github/lancedb/vectordb-recipes/blob/main/tutorials/feature-engineering/feature-engineering-101.ipynb" rel="noreferer, ,noopener" target="_blank"><img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open In Colab" /></a> [View on GitHub](https://github.com/lancedb/vectordb-recipes/tree/main/tutorials/feature-engineering/feature-engineering-101.ipynb) | This example demonstrates how to use LanceDB's feature engineering platform to add new derived features.
-| **Materialized Views** <br /> <a href="https://colab.research.google.com/github/lancedb/vectordb-recipes/blob/main/tutorials/feature-engineering/materialized-views.ipynb" rel="noreferer, ,noopener" target="_blank"><img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open In Colab" /></a> [View on GitHub](https://github.com/lancedb/vectordb-recipes/tree/main/tutorials/feature-engineering/materialized-views.ipynb) | This example shows how to create materialized views: query results persisted as physical tables.
-
-
-## Read the docs {#read-the-docs}
-
-The relevant section of the documentation are listed below.
-
-| Feature | Description |
-|:--------|:------------|
-| [Feature engineering](/feature-engineering) | The three ways to derive columns and tables. |
-| [Materialized views](/feature-engineering/materialized-views) | Derive a table from a query and refresh it incrementally. |
-| [Computed columns](/feature-engineering/add-computed-column) | Declare a column from an expression and fill it. |

docs/web/tutorials/feature-engineering/materialized-views.mdx

@@ -0,0 +1,23 @@
+---
+title: "Materialized views"
+sidebarTitle: "Materialized Views"
+description: "Persist query results as physical tables and keep them current."
+---
+
+Creates [materialized views](/management/materialized-view): query results
+persisted as physical tables, brought up to date by a
+[refresh](/feature-engineering/materialized-views).
+
+<Note>
+This example is a runnable notebook in the
+[vectordb-recipes](https://github.com/lancedb/vectordb-recipes) repository rather than a page here.
+</Note>
+
+<CardGroup cols={2}>
+  <Card title="Open in Colab" icon="google" href="https://colab.research.google.com/github/lancedb/vectordb-recipes/blob/main/tutorials/feature-engineering/materialized-views.ipynb">
+    Run it end to end in the browser.
+  </Card>
+  <Card title="View on GitHub" icon="github" href="https://github.com/lancedb/vectordb-recipes/tree/main/tutorials/feature-engineering/materialized-views.ipynb">
+    Read the source.
+  </Card>
+</CardGroup>