fix: escape $ in .woodpecker/edge-subpath.yml bash array expansion

Woodpecker YAML preprocessor reads ${...} as its own variable
substitution and fails on bash array expansion "${ARR[@]}" with
"missing closing brace". Escape as $${...} so Woodpecker emits
a literal $ to the shell.

Fixes CI pipeline error=generic "missing closing brace" on
pipelines #1408 and #1409.

.woodpecker/edge-subpath.yml

@@ -158,7 +158,7 @@ steps:
         )
 
         FAILED=0
-        for handler in "${REQUIRED_HANDLERS[@]}"; do
+        for handler in "$${REQUIRED_HANDLERS[@]}"; do
           if grep -q "$handler" "$CADDYFILE"; then
             echo "[PASS] Found handler: $handler"
           else