fix(provision): use $USERNAME/$EMAIL directly — Woodpecker 3.x env vars

Woodpecker 3.x exposes pipeline variables with their original key names
(USERNAME, EMAIL), not CI_PIPELINE_VARIABLE_ prefix.

.woodpecker/provision-user.yml

@@ -12,16 +12,10 @@ steps:
   - name: validate-inputs
     image: alpine
     commands:
-      - env | grep -i "CI_\|USERNAME\|EMAIL\|PROVISION" | sort || true
       - |
-        USERNAME="$CI_PIPELINE_VARIABLE_USERNAME"
-        EMAIL="$CI_PIPELINE_VARIABLE_EMAIL"
-        # Fallback: try without VARIABLE_ prefix (Woodpecker 3.x may use different format)
-        [ -z "$USERNAME" ] && USERNAME="$CI_PIPELINE_DEPLOY_TASK"
-        echo "DEBUG: USERNAME=$USERNAME EMAIL=$EMAIL"
-        echo "DEBUG: All CI vars:" && env | grep ^CI_ | sort
         if [ -z "$USERNAME" ] || [ -z "$EMAIL" ]; then
           echo "ERROR: USERNAME and EMAIL variables are required"
+          echo "Trigger with: POST /api/repos/1/pipelines {branch:master, variables:{USERNAME:x, EMAIL:y}}"
           exit 1
         fi
         echo "Provisioning user: $USERNAME ($EMAIL)"