fix: catch KeyboardInterrupt in exit cleanup handlers (#3257)

except Exception does not catch KeyboardInterrupt (inherits from
BaseException). A second Ctrl+C during exit cleanup aborts pending
writes — Honcho observations dropped, SQLite sessions left unclosed,
cron job sessions never marked ended.

Changed to except (Exception, KeyboardInterrupt) at all five sites:
- cli.py: honcho.shutdown() and end_session() in finally exit block
- run_agent.py: _flush_honcho_on_exit atexit handler
- cron/scheduler.py: end_session() and close() in job finally block

Tests exercise the actual production code paths and confirm
KeyboardInterrupt propagates without the fix.

Co-authored-by: dieutx <dangtc94@gmail.com>

cli.py

@@ -7163,13 +7163,13 @@ class HermesCLI:
             if self.agent and getattr(self.agent, '_honcho', None):
                 try:
                     self.agent._honcho.shutdown()
-                except Exception:
+                except (Exception, KeyboardInterrupt):
                     pass
             # Close session in SQLite
             if hasattr(self, '_session_db') and self._session_db and self.agent:
                 try:
                     self._session_db.end_session(self.agent.session_id, "cli_close")
-                except Exception as e:
+                except (Exception, KeyboardInterrupt) as e:
                     logger.debug("Could not close session in DB: %s", e)
             _run_cleanup()
             self._print_exit_summary()