fix(ci): use jq for JSON encoding in variable migration

Values with special characters (URLs, spaces) broke raw string interpolation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Dev User

.github/workflows/migrate-secrets-to-vars.yml

@@ -92,12 +92,16 @@ jobs:
               continue
             fi
 
+            # Build JSON payloads with jq to handle special characters
+            PATCH_BODY=$(jq -n --arg v "$VALUE" '{value: $v}')
+            POST_BODY=$(jq -n --arg n "$VAR_NAME" --arg v "$VALUE" '{name: $n, value: $v}')
+
             # Try update first (PATCH), fall back to create (POST)
             HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" -X PATCH \
               "https://api.github.com/repos/${REPO}/actions/variables/${VAR_NAME}" \
               -H "Authorization: Bearer ${GH_TOKEN}" \
               -H "Accept: application/vnd.github+json" \
-              -d "{\"value\":\"${VALUE}\"}")
+              -d "$PATCH_BODY")
 
             if [ "$HTTP_CODE" = "204" ]; then
               echo "UPDATED: $VAR_NAME"
@@ -107,7 +111,7 @@ jobs:
                 "https://api.github.com/repos/${REPO}/actions/variables" \
                 -H "Authorization: Bearer ${GH_TOKEN}" \
                 -H "Accept: application/vnd.github+json" \
-                -d "{\"name\":\"${VAR_NAME}\",\"value\":\"${VALUE}\"}")
+                -d "$POST_BODY")
 
               if [ "$HTTP_CODE" = "201" ]; then
                 echo "CREATED: $VAR_NAME"