add claude skills

skills/dbt-create-mart/mart_dim_template.sql

@@ -0,0 +1,10 @@
+-- Dimension model: deduplicated entity list from staging or transform.
+-- Provide one row per unique entity (customer, product, employee, etc.)
+
+select distinct
+    <natural_key>               as <entity>_key,
+    <descriptive_field_1>       as <readable_field_1>,
+    <descriptive_field_2>       as <readable_field_2>
+
+from {{ ref('<stg_or_trf_model>') }}
+where <natural_key> is not null