docs: rename DuckDB section to MotherDuck in connect-project (#522)

The DuckDB warehouse section actually describes MotherDuck connections,
so rename the heading, card, and dbt version note accordingly. An anchor
tag preserves the old #duckdb link to avoid breaking existing references.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: joaoviana

get-started/setup-lightdash/connect-project.mdx

@@ -45,7 +45,7 @@ We currently support:
 
   <Card title="ClickHouse" icon="container-storage" href="#clickhouse" />
 
-  <Card title="DuckDB" icon="database" href="#duckdb" />
+  <Card title="MotherDuck" icon="database" href="#motherduck" />
 
   <Card title="Athena" icon="aws" href="#athena" />
 
@@ -704,7 +704,8 @@ This controls what day is the start of the week in Lightdash. `Auto` sets it to
 
 ***
 
-### DuckDB
+<a id="duckdb"></a>
+### MotherDuck
 
 Lightdash supports DuckDB project connections through [MotherDuck](https://motherduck.com/).
 
@@ -736,7 +737,7 @@ This controls what day is the start of the week in Lightdash. `Auto` sets it to
 
 ##### dbt version
 
-DuckDB connections in Lightdash require dbt `v1.8` or later.
+MotherDuck connections in Lightdash require dbt `v1.8` or later.
 
 If you work with dbt locally, your `profiles.yml` should look similar to this: