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/update-browserslist-db/utils.js

@@ -0,0 +1,25 @@
+const { EOL } = require('os')
+
+const getFirstRegexpMatchOrDefault = (text, regexp, defaultValue) => {
+  regexp.lastIndex = 0 // https://stackoverflow.com/a/11477448/4536543
+  let match = regexp.exec(text)
+  if (match !== null) {
+    return match[1]
+  } else {
+    return defaultValue
+  }
+}
+
+const DEFAULT_INDENT = '  '
+const INDENT_REGEXP = /^([ \t]+)[^\s]/m
+
+module.exports.detectIndent = text =>
+  getFirstRegexpMatchOrDefault(text, INDENT_REGEXP, DEFAULT_INDENT)
+module.exports.DEFAULT_INDENT = DEFAULT_INDENT
+
+const DEFAULT_EOL = EOL
+const EOL_REGEXP = /(\r\n|\n|\r)/g
+
+module.exports.detectEOL = text =>
+  getFirstRegexpMatchOrDefault(text, EOL_REGEXP, DEFAULT_EOL)
+module.exports.DEFAULT_EOL = DEFAULT_EOL