fix: remove conflicting CSS that broke terminal sizing

- Remove second .terminal-wrapper.mobile definition that overrode position:absolute
- Add flex display to .xterm for proper viewport filling
- Add position:relative to mobile terminal-container
- Remove manual dimension setting workaround from terminal.tsx
- Root cause: CSS specificity conflict caused FitAddon to read height=0

apps/web/src/components/terminal.tsx

@@ -197,15 +197,7 @@ export const TerminalComponent: React.FC<TerminalProps> = ({
     term.loadAddon(fitAddon);
     term.loadAddon(new WebLinksAddon());
 
-    // Ensure container has explicit dimensions before xterm initializes
-    const container = terminalRef.current;
-    const parentRect = container.parentElement?.getBoundingClientRect();
-    if (parentRect) {
-      container.style.width = `${parentRect.width}px`;
-      container.style.height = `${parentRect.height}px`;
-    }
-
-    term.open(container);
+    term.open(terminalRef.current);
 
     // Connect WebSocket
     const ws = connectWebSocket();