Automate Google login with rbw password lookup

- Add rbw integration to retrieve credentials from Bitwarden vault
- Automate email/password entry with Selenium WebDriver
- Handle 2FA by falling back to manual completion
- Add clipboard support for Wayland (wl-copy) and X11 (xclip)
- Add CLI flags: --entry, --no-copy, --manual
- Add DESIGN.md documenting the implementation approach

flake.nix

@@ -12,6 +12,8 @@
         pkgs.python3Packages.selenium
         pkgs.chromedriver
         pkgs.chromium
+        pkgs.xclip
+        pkgs.wl-clipboard
       ];
     in {
       devShells.${system}.default = pkgs.mkShell {