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/is-path-inside/index.d.ts

@@ -0,0 +1,27 @@
+/**
+Check if a path is inside another path.
+
+Note that relative paths are resolved against `process.cwd()` to make them absolute.
+
+_Important:_ This package is meant for use with path manipulation. It does not check if the paths exist nor does it resolve symlinks. You should not use this as a security mechanism to guard against access to certain places on the file system.
+
+@example
+```
+import isPathInside = require('is-path-inside');
+
+isPathInside('a/b/c', 'a/b');
+//=> true
+
+isPathInside('a/b/c', 'x/y');
+//=> false
+
+isPathInside('a/b/c', 'a/b/c');
+//=> false
+
+isPathInside('/Users/sindresorhus/dev/unicorn', '/Users/sindresorhus');
+//=> true
+```
+*/
+declare function isPathInside(childPath: string, parentPath: string): boolean;
+
+export = isPathInside;