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_modules/balanced-match/package.json

@@ -0,0 +1,48 @@
+{
+  "name": "balanced-match",
+  "description": "Match balanced character pairs, like \"{\" and \"}\"",
+  "version": "1.0.2",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/juliangruber/balanced-match.git"
+  },
+  "homepage": "https://github.com/juliangruber/balanced-match",
+  "main": "index.js",
+  "scripts": {
+    "test": "tape test/test.js",
+    "bench": "matcha test/bench.js"
+  },
+  "devDependencies": {
+    "matcha": "^0.7.0",
+    "tape": "^4.6.0"
+  },
+  "keywords": [
+    "match",
+    "regexp",
+    "test",
+    "balanced",
+    "parse"
+  ],
+  "author": {
+    "name": "Julian Gruber",
+    "email": "mail@juliangruber.com",
+    "url": "http://juliangruber.com"
+  },
+  "license": "MIT",
+  "testling": {
+    "files": "test/*.js",
+    "browsers": [
+      "ie/8..latest",
+      "firefox/20..latest",
+      "firefox/nightly",
+      "chrome/25..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest",
+      "android-browser/4.2..latest"
+    ]
+  }
+}