fix(dbt): read percentages DfE writes as "34%" (C2)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pipeline/transform/macros/safe_numeric.sql

@@ -3,7 +3,9 @@
   Casts a string column to numeric, treating any non-numeric value as NULL.
   Handles all EES suppression codes (z, c, x, q, u, etc.) without needing
   an explicit list — any string that doesn't look like a number becomes NULL.
+  A trailing percent sign is accepted: DfE's 2023/24 KS2 information file
+  writes percentages as "34%" (audit C2).
 #}
 {% macro safe_numeric(col) -%}
-    CASE WHEN {{ col }} ~ '^-?[0-9]+(\.[0-9]+)?$' THEN {{ col }}::numeric ELSE NULL END
+    CASE WHEN {{ col }} ~ '^-?[0-9]+(\.[0-9]+)?%?$' THEN rtrim({{ col }}, '%')::numeric ELSE NULL END
 {%- endmacro %}