fix: install sudo so agent-browser --with-deps can run apt-get

[hilr]

Summary

The image build fails at agent-browser install --with-deps (line 35 of the Dockerfile):

Running: sudo apt-get update
⚠ Could not run apt-get update: No such file or directory (os error 2)
...
✗ Failed to install system dependencies: could not run install command: No such file or directory (os error 2)

python:3.12-slim does not ship sudo, so agent-browser's sudo apt-get ... invocations fail with ENOENT. Install sudo in the second apt-get list (the one that already pulls in gh/openssh-client/docker-ce-cli).

Unrelated to #68 (git-lfs) — that one touches line 9, this one touches line 30, so they merge cleanly.

Test plan

• Dockerfile diff is one token added to an existing apt-get install line
• rebuild the image and confirm agent-browser install --with-deps completes

🤖 Generated with Claude Code

[hilr]

不需要装 sudo——构建那步本身是 root，--with-deps 却硬调 sudo apt-get 是多余的。改去掉 --with-deps（Dockerfile 已手动装了浏览器要的库）。