Global code ovehaul - remove CAS and other, add 15 minute greet check

- Remove CAS, as it no longer works for us
- Remove other checks
- Implement 15 minute greet timeout check
- Fix chat logos
- Ditch thirdparty logger, use stdlib log facility wrapper for logging

internal/moon/exitCode.go

@@ -0,0 +1,25 @@
+package moon
+
+import "os"
+
+// ExitCode reports the status the process should leave with on a clean return
+// from run(). It is zero while the bot is running normally, and 128 + the
+// signal's number once a termination signal has begun the shutdown — the Unix
+// convention a supervisor can use to tell "stopped with a signal" from "stopped
+// cleanly", which D33 left permanently 0 before it.
+//
+// It never reports an error status: a failed shutdown still returns an error
+// from run(), and main exits 1 over that, the same as before.
+func ExitCode() int {
+	return int(exitCode.Load())
+}
+
+// recordExitCode stores the status the given terminating signal should leave.
+// Only the first termination signal matters — the handler goroutine returns
+// after one — so a later write cannot pass either.
+func recordExitCode(s os.Signal) {
+	// The value is one of a fixed table of 128+n, never a caller-supplied int.
+	exitCode.Store(int32(exitCodeFor(s))) //nolint:gosec // G115: exitCodeFor returns only 130, 131, 143 or 0.
+}
+
+/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */