test: make opencode-resize and split-pane browser tests environment-proof

- opencode-resize: record WebSocket resize frames as well as POST /resize,
  seed the needsRefresh test with real PTY output, skip the OpenCode close
  modal test when opencode is not installed
- split-pane: send the marker with useMux:false (plain prompts otherwise go
  through tmux send-keys, which test mode does not have) and retry past
  Codeman's own post-create clear

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JrzFKEdBLwVfu6ev2ZscJS

test/opencode-resize.test.ts

@@ -11,6 +11,7 @@
  * Run: npx vitest run test/opencode-resize.test.ts
  */
 
+import { execSync } from 'node:child_process';
 import { describe, it, expect, beforeAll, afterAll } from 'vitest';
 import { chromium, type Browser, type BrowserContext, type Page } from 'playwright';
 import { WebServer } from '../src/web/server.js';
@@ -18,6 +19,15 @@ import { WebServer } from '../src/web/server.js';
 const PORT = 3211;
 const BASE_URL = `http://localhost:${PORT}`;
 
+const HAS_OPENCODE = (() => {
+  try {
+    execSync('command -v opencode', { stdio: 'ignore', shell: '/bin/bash' });
+    return true;
+  } catch {
+    return false;
+  }
+})();
+
 let server: WebServer;
 let browser: Browser;
 
@@ -103,6 +113,19 @@ describe('OpenCode session initial resize', () => {
 
     // Intercept resize API calls to track when they happen
     const resizeCalls: Array<{ url: string; cols: number; rows: number }> = [];
+    // While the WebSocket is connected, resizes go out as {t:'z',c,r} frames
+    // instead of POST /resize, so record both transports.
+    page.on('websocket', (ws) => {
+      ws.on('framesent', (frame) => {
+        try {
+          const msg = JSON.parse(String(frame.payload));
+          if (msg.t === 'z') resizeCalls.push({ url: ws.url() + '#' + sessionIdForWs, cols: msg.c, rows: msg.r });
+        } catch {
+          /* not JSON */
+        }
+      });
+    });
+    let sessionIdForWs = '';
     await page.route('**/api/sessions/*/resize', async (route) => {
       const request = route.request();
       const body = request.postDataJSON();
@@ -128,6 +151,7 @@ describe('OpenCode session initial resize', () => {
     });
 
     expect(sessionId).toBeTruthy();
+    sessionIdForWs = sessionId;
 
     // Call selectSession (which is what runOpenCode does after fix)
     await page.evaluate(async (sid: string) => {
@@ -233,7 +257,23 @@ describe('OpenCode session initial resize', () => {
       await app.selectSession(sid);
     }, sessionId);
 
-    await page.waitForTimeout(300);
+    // The handler only resizes after it has replayed a NON-EMPTY terminal
+    // buffer, so give the session a real PTY with some output first.
+    await page.evaluate(async (sid: string) => {
+      await fetch(`/api/sessions/${sid}/shell`, { method: 'POST' });
+      const deadline = Date.now() + 5000;
+      for (;;) {
+        await fetch(`/api/sessions/${sid}/input`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ input: 'echo needs-refresh-seed\r', useMux: false }),
+        });
+        await new Promise((r) => setTimeout(r, 400));
+        const res = await fetch(`/api/sessions/${sid}/terminal?full=1`);
+        if ((((await res.json())?.data?.terminalBuffer as string) ?? '').includes('needs-refresh-seed')) break;
+        if (Date.now() > deadline) throw new Error('seed output never appeared');
+      }
+    }, sessionId);
 
     // Intercept resize calls
     const resizeCalls: Array<{ url: string }> = [];
@@ -278,7 +318,7 @@ describe('OpenCode close modal text', () => {
     await context?.close();
   });
 
-  it('shows "Kill Tmux & OpenCode" for opencode sessions', async () => {
+  it.skipIf(!HAS_OPENCODE)('shows "Kill Tmux & OpenCode" for opencode sessions', async () => {
     ({ context, page } = await freshPage());
     await navigateAndWait(page);
 

test/split-pane-terminal.browser.test.ts

@@ -113,18 +113,21 @@ describe('SplitTerminalPane in a real browser', () => {
       // own startup can race an early write and, on this box, a startup
       // script issues a `clear` that erases scrollback (modern ncurses
       // `clear` emits \x1b[3J) if the input lands before the shell is ready.
-      await fetch(`/api/sessions/${id}/input`, {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ input: 'PRE_EXISTING_MARKER\r' }),
-      });
-      const deadline = Date.now() + 5000;
+      // Codeman itself writes `clear` into a NEW shell session ~100ms after
+      // creating it, which can erase an early marker, so re-send until the
+      // marker is present in the capture rather than writing once.
+      const deadline = Date.now() + 8000;
       for (;;) {
+        await fetch(`/api/sessions/${id}/input`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ input: 'PRE_EXISTING_MARKER\r', useMux: false }),
+        });
+        await new Promise((r) => setTimeout(r, 400));
         const res2 = await fetch(`/api/sessions/${id}/terminal?full=1`);
         const buffer = (await res2.json())?.data?.terminalBuffer ?? '';
         if (buffer.includes('PRE_EXISTING_MARKER')) break;
         if (Date.now() > deadline) throw new Error('marker never landed in ?full=1 capture: ' + JSON.stringify(buffer));
-        await new Promise((r) => setTimeout(r, 200));
       }
       return id;
     });
@@ -166,7 +169,7 @@ describe('SplitTerminalPane in a real browser', () => {
     await page.evaluate(async (id) => {
       await fetch(`/api/sessions/${id}`, { method: 'DELETE' });
     }, sessionId);
-  });
+  }, 20000);
 
   it('gates app-level chords out of Pane B instead of forwarding their raw bytes', async () => {
     // Regression guard for PR #453's Ctrl+K/Alt+1/Alt+B leak: Pane B had no