fix(cron): send a paste-mode prompt's Enter as its own write

A cron job in "Paste (direct)" input mode wrote `<text>\r` into the pane
in one piece. Claude Code (measured on 2.1.283) takes a burst of about a
hundred characters as a paste, so the `\r` landed as a newline and the
prompt sat unsent on the composer while the run reported `prompt_sent`.

Delivery now lives in `deliverCronPrompt()`. Paste mode writes the text
raw, waits CRON_PASTE_ENTER_DELAY_MS (300 ms), sends `\r` as a separate
write down the same PTY (so it cannot overtake the text), and arms the
session's composer check through the new public
`Session.verifySubmitted()`, which re-presses Enter while the prompt is
still visibly unsent. A session with nothing to write to now fails the
run instead of reporting the prompt as sent. Typed mode is unchanged.

Verified on an isolated instance: a paste-mode job with a 104-character
prompt submitted on the first Enter and Claude answered.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/session.ts

@@ -4207,6 +4207,16 @@ export class Session extends EventEmitter {
     return false;
   }
 
+  /**
+   * Arm the composer check for a prompt that went out some other way than
+   * `writeViaMux`, e.g. cron's paste mode, which writes the body raw and its Enter
+   * separately. `text` is what the composer line starts with while the prompt is still
+   * unsent; the check re-presses Enter only while that holds.
+   */
+  verifySubmitted(text: string): void {
+    this._verifySubmitted(`${text}\r`);
+  }
+
   /**
    * Arm the composer check for a write that carried Enter (session-submit-verifier.ts):
    * Claude Code 2.1.277+ ignores Enter for the first 30-50 s after the composer paints,