fix: Improve terminal buffer handling and replay performance

- Add chunked replay (8KB chunks with 10ms delay) to avoid overwhelming xterm.js
- Add clear-buffer server command to reset terminal history
- Add clear buffer button in terminal header
- Filter out tiny resize events during CSS transitions (ignore < 20x5)
- Remove premature fit() call from init - wait for onBecameVisible

server/services/terminal.ts

@@ -187,6 +187,10 @@ export function startTerminalServer() {
           } else if (msg.type === 'resize' && msg.cols && msg.rows) {
             session.pty.resize(msg.cols, msg.rows)
             console.log(`[Terminal] Session ${sessionId} resized to ${msg.cols}x${msg.rows}`)
+          } else if (msg.type === 'clear-buffer') {
+            session.outputBuffer = []
+            console.log(`[Terminal] Buffer cleared for session ${sessionId}`)
+            ws.send(JSON.stringify({ type: 'buffer-cleared' }))
           } else if (msg.type === 'request-replay') {
             // Client requests fresh replay (used when terminal becomes visible)
             console.log(`[Terminal] Replay requested, buffer has ${session.outputBuffer.length} chunks`)