A from-the-ground-up map: the language-level primitives (threads, goroutines, async/await, locks, channels, memory models) and how they connect to the system-level concerns already in the Study List — contention, races, optimistic vs. pessimistic locking, compare-and-swap, and write skew. The throughline: the same hazards reappear at every scale, from one process to a fleet.
