pub fn on_panic(info: &PanicInfo<'_>) -> !Expand description
Shared message-only panic handler for both targets. Pushes the panic info
into the ring (alongside the pre-panic context that’s already there), then
synchronously drains the ring via the raw FIFO poker — the async drain
task is gone (or never started) so it can’t service the ring for us. After
the drain, halts so the fault stays visible. No stack walk: message-only
on both targets (deliberate, symmetric), which is why neither esp-backtrace
nor esp-println is pulled in. The binary’s #[panic_handler] is a
one-line wrapper around this.