fix: replace shell ${VAR} with $VAR to avoid Woodpecker pre-processing

Woodpecker interprets ${...} as its own template syntax and strips
unrecognized variables. Using $VAR (no braces) passes through to bash.

.woodpecker/build.yml

@@ -29,7 +29,8 @@ steps:
 
       set -e
 
-      IMAGE_TAG="${CI_COMMIT_TAG:-latest}"
+      IMAGE_TAG="$CI_COMMIT_TAG"
+      if [ -z "$IMAGE_TAG" ]; then IMAGE_TAG="latest"; fi
 
       # 确保网络存在
       docker network create likedream-net 2>/dev/null || true
@@ -72,7 +73,7 @@ steps:
           HEALTHY=true
           break
         fi
-        echo "  等待新容器就绪... (${i}/15)"
+        echo "  等待新容器就绪... ($i/15)"
         sleep 2
       done
 
@@ -87,7 +88,7 @@ steps:
       # 切换 1Panel 代理到备用端口
       echo "=== 切换 1Panel 反代 :$PORT_ACTIVE → :$PORT_STANDBY ==="
       docker exec 1Panel-openresty-ESmn \
-        sed -i "s|:${PORT_ACTIVE}|:${PORT_STANDBY}|g" \
+        sed -i "s|:$PORT_ACTIVE|:$PORT_STANDBY|g" \
         /www/sites/tianshen/proxy/api.conf
       docker exec 1Panel-openresty-ESmn nginx -s reload
       echo "   Nginx 热加载完成（零中断）✓"
@@ -112,7 +113,7 @@ steps:
       # 切回 1Panel 代理到活跃端口
       echo "=== 切回 1Panel 反代 :$PORT_STANDBY → :$PORT_ACTIVE ==="
       docker exec 1Panel-openresty-ESmn \
-        sed -i "s|:${PORT_STANDBY}|:${PORT_ACTIVE}|g" \
+        sed -i "s|:$PORT_STANDBY|:$PORT_ACTIVE|g" \
         /www/sites/tianshen/proxy/api.conf
       docker exec 1Panel-openresty-ESmn nginx -s reload
       echo "   Nginx 热加载完成（零中断）✓"