fix: Remove duplicate prompt by handling echo in JavaScript

The double prompt issue was caused by both WASM and JavaScript showing prompts.

Changes:
- WASM: Removed prompt echo from process_input (src/wasm.rs)
  Web UI now handles all display, WASM just processes commands
- JavaScript: Echo ">command" to output history when user submits
  This makes the prompt+command permanent in scroll history
  InputArea shows live "> " that disappears after Enter

Flow now:
1. User sees "> " in InputArea (live, not in history)
2. User types "look" and presses Enter
3. JavaScript adds ">look" to permanent output history
4. InputArea disappears while processing
5. Game output appears
6. New InputArea shows "> " for next command

Result: Single prompt visible at any time, behaves like traditional terminal.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: skeptomai

src/wasm.rs

@@ -433,9 +433,7 @@ impl WasmInterpreter {
 
     /// Process text input
     fn process_input(&mut self, inst: &Instruction, input: &str) -> Result<(), String> {
-        self.display.print(">").ok();
-        self.display.print(input).ok();
-        self.display.print_char('\n').ok();
+        // Note: Web UI handles echoing the prompt and command, so we don't print it here
 
         let text_buffer = self.get_operand(inst, 0)?;
         let parse_buffer = if inst.operands.len() > 1 {

web/js/main.js

@@ -490,6 +490,13 @@ function App() {
     if (!interpreter) return;
 
     try {
+      // Echo the command to output with prompt (since WASM no longer does this)
+      setGameState(prev => ({
+        ...prev,
+        outputLines: [...prev.outputLines, `>${command}`],
+        waitingForInput: false,
+      }));
+
       // Send command to WASM interpreter
       interpreter.provide_input(command);