fix(terminal): skip PSReadLine repaint nudge before shell-ready

The form feed was written directly to the subprocess, bypassing Session
write ordering. Routing it through write() would be worse — a queued form
feed flushes after the buffered startup command at an arbitrary later
moment, when the foreground/prompt gates no longer hold. The nudge is
cosmetic, so skip it during the pre-ready window instead.

src/main/daemon/session.test.ts

@@ -477,6 +477,20 @@ describe('Session', () => {
       expect(subprocess.written).toEqual([])
     })
 
+    it('does not send or queue a form feed before shell-ready', async () => {
+      createSession({ shellReadySupported: true })
+      subprocess.foregroundProcess = 'powershell.exe'
+      subprocess.simulateData('PS C:\\Users\\me> ')
+      await vi.advanceTimersByTimeAsync(10)
+      // Why: a queued form feed would flush after the startup command at an
+      // arbitrary later moment, when the prompt gates no longer hold.
+      withPlatform('win32', () => session.clearScrollback())
+      expect(subprocess.written).toEqual([])
+      subprocess.simulateData('\x1b]777;orca-shell-ready\x07\r\nPS C:\\Users\\me> ')
+      await vi.advanceTimersByTimeAsync(10)
+      expect(subprocess.written).toEqual([])
+    })
+
     it('does not send a form feed at a PowerShell continuation prompt', async () => {
       createSession()
       subprocess.foregroundProcess = 'powershell.exe'

src/main/daemon/session.ts

@@ -305,6 +305,13 @@ export class Session {
     if (process.platform !== 'win32') {
       return
     }
+    // Why: before shell-ready, write() would queue the form feed behind the
+    // buffered startup command and deliver it at an arbitrary later moment,
+    // when the foreground/prompt gates below no longer hold. The nudge is
+    // cosmetic — skip it rather than defer it.
+    if (this._shellState === 'pending' || this.postReadyFlushGate.isPending) {
+      return
+    }
     if (!isPowerShellProcess(this.subprocess.getForegroundProcess())) {
       return
     }