🐛 fix: JTAG reboot 'Already running' error after rst -system

rst -system inherently resumes ARM execution on Zynq.
The subsequent 'con' command fails with 'Already running'
because the core is already executing after system reset.

Fix: wrap 'con' in 'catch {}' — if core is already running
the error is silently caught; if stopped, con resumes it.
xsct exits 0 (success) in both cases.

src/reboot_manager.py

@@ -214,7 +214,7 @@ rst -system
 after 1500
 
 puts "INFO: Resuming ARM execution..."
-con
+catch { con }
 
 puts "INFO: System reset complete — disconnecting..."
 disconnect