fix: correct DockerfileUbuntu package list, add rustup install, and fix terminal init sequence

- Fix typo in DockerfileDrive COPY command (COpy -> COPY)
- Add xterm, valgrind, ack, irssi, lynx packages to DockerfileUbuntu
- Add rustup installation with nightly toolchain in DockerfileUbuntu
- Fix r binary move path in DockerfileUbuntu (add trailing /r)
- Remove CMD ["r"] from DockerfileUbuntu
- Replace terminal.html onopen handler: call fitAddon.fit() and send form feed instead of hardcoded green text
- Add $HOME/bin to PATH in .bashrc
- Add resize command to .bashrc for terminal geometry sync
- Delete terminal/.rcontext.txt file entirely

src/snek/templates/terminal.html

@@ -33,7 +33,11 @@
         const socket = new WebSocket(url);
         socket.binaryType = "arraybuffer";  // Support binary data
 
-        socket.onopen = () => term.write("\x1b[32mConnected to Molodetz\x1b[0m\r\n");
+        socket.onopen = () => { 
+            fitAddon.fit();
+            term.write("\x0C");
+            
+        }
 
         socket.onmessage = (event) => {
             const data = new Uint8Array(event.data);