feat: Add presence heartbeat for Matrix online status

- matrix-gateway: POST /internal/matrix/presence/online endpoint
- usePresenceHeartbeat hook with activity tracking
- Auto away after 5 min inactivity
- Offline on page close/visibility change
- Integrated in MatrixChatRoom component

node-network-app/node_modules/resolve/test/module_dir/xmodules/aaa/index.js

@@ -0,0 +1 @@
+module.exports = function (x) { return x * 100; };

node-network-app/node_modules/resolve/test/module_dir/ymodules/aaa/index.js

@@ -0,0 +1 @@
+module.exports = function (x) { return x + 100; };

node-network-app/node_modules/resolve/test/module_dir/zmodules/bbb/main.js

@@ -0,0 +1 @@
+module.exports = function (n) { return n * 111; };

node-network-app/node_modules/resolve/test/module_dir/zmodules/bbb/package.json

@@ -0,0 +1,3 @@
+{
+  "main": "main.js"
+}