Mobile reactions and WS reconnection

* [feat] Add reaction menu item for mobile clients.

* [fix] Reconnection to the websocket with exponential backoff.

* [chore] Dev flake.

* [hack] Push to my personal gcr.

flake.nix

@@ -0,0 +1,28 @@
+{
+  description = "Node+yarn dev shell flake";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    systems.url = "github:nix-systems/default";
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+      inputs.systems.follows = "systems";
+    };
+  };
+
+  outputs =
+    { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          packages = with pkgs; [
+            nodejs_24
+            yarn
+          ];
+        };
+      }
+    );
+}