fix(ci): resolve PG 17 showcase test failure

Add missing dir to test:integration:showcase task so mise --env tls
runs from tests/ where mise.tls.toml exists, correctly loading TLS
environment variables (CS_DATABASE__HOST and CS_DATABASE__PORT).

Fix quoting bug in proxy:up container detection where unquoted variable
expansions collapsed multi-line docker ps output, causing grep and cut
to select the wrong container when multiple postgres containers are
running.

Author: tobyhede

mise.toml

@@ -83,13 +83,13 @@ if [ "${CS_DATABASE__HOST}" == "localhost" ]; then
   {% raw %}
   running_postgres="$(docker ps --filter "name=postgres" --filter "health=healthy" --format "{{.Names}};{{.Ports}}")"
   {% endraw %}
-  if [ -z "${running_postgres}" ] || [ -z $(echo ${running_postgres} | grep ${CS_DATABASE__PORT}) ] ; then
+  if [ -z "${running_postgres}" ] || [ -z "$(echo "${running_postgres}" | grep "${CS_DATABASE__PORT}")" ] ; then
     echo "error: Could not detect a running, healthy postgres container with port ${CS_DATABASE__PORT}"
     echo "error: Try running 'mise run postgres:up' to start a container"
     exit 68
   fi
-  echo $running_postgres
-  export CS_DATABASE__HOST=$(echo $running_postgres | grep ${CS_DATABASE__PORT} | cut -d ';' -f 1)
+  echo "${running_postgres}"
+  export CS_DATABASE__HOST=$(echo "${running_postgres}" | grep "${CS_DATABASE__PORT}" | cut -d ';' -f 1)
   echo "Using postgres running in container: ${CS_DATABASE__HOST}"
 fi
 
@@ -688,6 +688,7 @@ fi
 
 [tasks."test:integration:showcase"]
 description = "Run Showcase integration test"
+dir = "{{config_root}}/tests"
 run = """
 mise --env tls run proxy:up proxy-tls --extra-args "--detach --wait"
 mise --env tls run test:wait_for_postgres_to_quack --port 6432 --max-retries 20 --tls