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 %}

pipeline/transform/models/staging/stg_ees_ks2.yml

@@ -0,0 +1,22 @@
+version: 2
+
+unit_tests:
+  - name: stg_ees_ks2_reads_percentages_written_with_a_sign
+    description: >
+      DfE's 2023/24 KS2 information file writes percentages as "34%", and every
+      2023/24 percentage loaded as null (audit C2). Plain numbers still load;
+      suppression codes stay null. School 147411's 2023/24 figures are DfE's.
+    model: stg_ees_ks2
+    given:
+      - input: source('raw', 'ees_ks2_attainment')
+        rows:
+          - {school_urn: '147411', time_period: '202324', subject: 'Reading, writing and maths', breakdown_topic: 'All pupils', breakdown: 'Total', expected_standard_pupil_percent: '70'}
+          - {school_urn: '100000', time_period: '202425', subject: 'Reading, writing and maths', breakdown_topic: 'All pupils', breakdown: 'Total', expected_standard_pupil_percent: '79'}
+      - input: source('raw', 'ees_ks2_info')
+        rows:
+          - {school_urn: '147411', time_period: '202324', totpups: '818', telig: '112', ptfsm6cla1a: '34%', ptealgrp2: '56%', psenelk: '20%', psenele: 'c', ptmobn: '87.5%'}
+          - {school_urn: '100000', time_period: '202425', totpups: '792', telig: '105', ptfsm6cla1a: '32', ptealgrp2: 'x', psenelk: '14', psenele: '2', ptmobn: '87'}
+    expect:
+      rows:
+        - {urn: 147411, year: 202324, total_pupils: 818, rwm_expected_pct: 70, disadvantaged_pct: 34, eal_pct: 56, sen_support_pct: 20, sen_ehcp_pct: null, stability_pct: 87.5}
+        - {urn: 100000, year: 202425, total_pupils: 792, rwm_expected_pct: 79, disadvantaged_pct: 32, eal_pct: null, sen_support_pct: 14, sen_ehcp_pct: 2, stability_pct: 87}