Fix WebUI: podman_parse_time() rejected int timestamps from list endpoints

Found by exercising the AJAX endpoints directly against a real running
podman service (php -d display_errors=1 -r '...containers.php...') —
containers.php's list action crashed with an uncaught TypeError the
moment a real container existed. podman's libpod API is inconsistent
about container/volume timestamp encoding: inspect-style endpoints
return RFC3339 strings, but list-style endpoints (containers/json,
volumes/json) return raw Unix-epoch integers for the same logical
field. podman_parse_time() only accepted ?string, so any list call
with a real container blew up outright rather than merely
mis-rendering. Widened it to string|int|null and handle both.

Verified: containers.php's list action now returns correct JSON for
real running/exited containers, including their createdAt timestamps.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

webui/plugins/podman/include/helpers.php

@@ -42,13 +42,25 @@ function podman_format_duration(int $seconds): string
     return "{$minutes}m";
 }
 
-/** Converts a libpod RFC3339 timestamp (as found in inspect output) to a Unix timestamp, or null if unparsable. */
-function podman_parse_time(?string $rfc3339): ?int
+/**
+ * Converts a libpod timestamp to a Unix timestamp, or null if unparsable.
+ * Accepts both the RFC3339 strings `inspect`-style endpoints return and
+ * the raw Unix-epoch integers `list`-style endpoints return for the same
+ * logical field (e.g. containers/json's StartedAt/Created vs. inspect's)
+ * — verified live against a real podman system service, not just docs.
+ */
+function podman_parse_time(string|int|null $value): ?int
 {
-    if ($rfc3339 === null || $rfc3339 === '' || str_starts_with($rfc3339, '0001-01-01')) {
+    if ($value === null || $value === '') {
         return null;
     }
-    $ts = strtotime($rfc3339);
+    if (is_int($value)) {
+        return $value > 0 ? $value : null;
+    }
+    if (str_starts_with($value, '0001-01-01')) {
+        return null;
+    }
+    $ts = strtotime($value);
     return $ts === false ? null : $ts;
 }