Initial commit: Go SRE interview exercises

Includes solved 02-worker-pool and 09-safe-counter (mutex, atomic, sharded).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GbnJj9ZqEx9nUvzkjdwfMq

10-gotchas/ex11-method-set/main.go

@@ -0,0 +1,15 @@
+// PREDICT: does this compile? If not, why not, and what's the minimal fix?
+package main
+
+import "fmt"
+
+type Stringer interface{ String() string }
+
+type T struct{}
+
+func (t *T) String() string { return "T" }
+
+func main() {
+	var s Stringer = T{}
+	fmt.Println(s.String())
+}