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/ex05-slice-aliasing/main.go

@@ -0,0 +1,17 @@
+// PREDICT both printed slices. Explain the difference between the two appends.
+package main
+
+import "fmt"
+
+func main() {
+	a := []int{1, 2, 3, 4}
+
+	b := a[:2]
+	b = append(b, 99)
+	fmt.Println("after append to a[:2]  ->", a)
+
+	a = []int{1, 2, 3, 4}
+	c := a[:2:2]
+	c = append(c, 100)
+	fmt.Println("after append to a[:2:2] ->", a)
+}