fix: bump PocketIC server to 13.0.0 for ic0::env_var_count support

The station canister now uses the ic0::env_var_count API (via
dependencies), which PocketIC server 10.0.0 doesn't support. Bump
the server binary to 13.0.0 while keeping the pocket-ic crate at
10.0.0 (11+ requires Rust 1.88, project uses 1.87). The server
REST API changes between 10 and 13 are additive/non-breaking.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: aterga

scripts/run-integration-tests.sh

@@ -2,7 +2,7 @@
 
 set -eEuo pipefail
 
-POCKET_IC_SERVER_VERSION="10.0.0"
+POCKET_IC_SERVER_VERSION="13.0.0"
 
 SCRIPT=$(readlink -f "$0")
 SCRIPT_DIR=$(dirname "$SCRIPT")