fix: terminal size sync — resize message handler + xterm-256color default-terminal

extensions/remote-control/server/routes/stream.ts

@@ -22,6 +22,7 @@ import { readChunks } from "../../buffer/reader.js";
 import type { StateEvent } from "../../pi/events.js";
 import { SequenceCounter } from "../../sequence.js";
 import { ControlClient } from "../../tmux/control.js";
+import { resizeSession } from "../../tmux/manager.js";
 import { capturePane } from "../../tmux/snapshot.js";
 import type { WsClient, WsServer } from "../types.js";
 
@@ -155,6 +156,12 @@ function handleStreamConnection(
         if (ws.readyState !== 1) break;
         sendBinary(ws, buildBinaryFrame(chunk.seq, chunk.data));
       }
+    } else if (m.type === "resize") {
+      // IC-1 extension: client reports its actual terminal dimensions.
+      // Resize the tmux window so line-wrapping matches what the client sees.
+      const cols = typeof m.cols === "number" ? m.cols : 80;
+      const rows = typeof m.rows === "number" ? m.rows : 24;
+      resizeSession(sessionId, cols, rows).catch(() => {});
     } else if (m.type === "snapshot-request") {
       capturePane({ session: sessionId })
         .then((text) => {

extensions/remote-control/tmux/manager.ts

@@ -60,6 +60,15 @@ export async function spawnSession(opts: {
   await checkTmuxVersion();
   const { name, width = 120, height = 40, command = "" } = opts;
 
+  // Set default-terminal globally so programs inside tmux get xterm-256color
+  // and emit the escape sequences that SwiftTerm / xterm-compatible clients expect.
+  await execFileAsync("tmux", [
+    "set-option",
+    "-g",
+    "default-terminal",
+    "xterm-256color",
+  ]).catch(() => {}); // best-effort; older tmux may not support all options
+
   const args = [
     "new-session",
     "-d",
@@ -76,6 +85,28 @@ export async function spawnSession(opts: {
   return name;
 }
 
+/**
+ * Resize an existing session's window.
+ * Safe to call at any time; silently ignores unknown sessions.
+ */
+export async function resizeSession(
+  name: string,
+  cols: number,
+  rows: number,
+): Promise<void> {
+  const c = Math.max(1, Math.min(Math.round(cols), 500));
+  const r = Math.max(1, Math.min(Math.round(rows), 200));
+  await execFileAsync("tmux", [
+    "resize-window",
+    "-t",
+    name,
+    "-x",
+    String(c),
+    "-y",
+    String(r),
+  ]).catch(() => {}); // session may not exist yet; ignore
+}
+
 /**
  * List all tmux sessions with metadata.
  */