Share a chosen workspace folder and stop with the window

run.sh asks which host folder Claude may access, using the desktop's
folder picker (zenity, or kdialog on KDE; terminal prompt otherwise),
and mounts it read-write at /workspace. It opens at the last folder
used, refuses / and $HOME, and can be skipped with --workspace DIR.
The image creates /workspace and a ~/workspace symlink to it.

Closing Claude Desktop's window only hides the app, which left the
container running invisibly. The new entrypoint launch-claude.sh
watches the app's X windows and quits it once none is open or
minimized, so the container exits with it. run.sh adds --init for
signal handling and reaping.

Also add .gitignore for workspace/ and .env.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,2 @@
+workspace/
+.env