feat: fixed-height near-white input, terse-answer system prompt

server.js

@@ -63,7 +63,7 @@ app.post('/api/chat', async (req, res) => {
                 model: modelId,
                 max_tokens: 8192,
                 stream: true,
-                system: "You are Claude Code, Anthropic's official CLI for Claude.",
+                system: "You are Claude Code, Anthropic's official CLI for Claude.\n\nAnswer in the same language as the user. Give the shortest possible correct answer. No greetings, no filler, no emojis, no markdown formatting unless the user explicitly asks for code. Do not restate the question. Do not add caveats or disclaimers. Respond with just the answer — nothing else.",
                 messages: [{ role: 'user', content: text }],
             }),
         });