Exercise 2: What Actually Changed Since Chapter 8 — Possible Solution
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WHAT LOOKS IDENTICAL BETWEEN STEP 5 AND CHAPTER 8
------------------------------
Per this chapter, the route, the Zod schema, the safeParse
validation, and the Drizzle update call are all exactly the same
code written in Chapter 8 - nothing about the request-handling
mechanics changed.

WHAT ACTUALLY CHANGED
------------------------------
Per this chapter, Chapter 8 deliberately left the endpoint with no
authentication check at all - genuinely the bare-minimum version of
the gap, since Astro had no conventional place for one to even go
yet. Chapter 9 added exactly that missing piece. By the time this
capstone reaches Step 5, that added check is what determines whether
the identical-looking submission actually succeeds - logged in, it
behaves exactly as it did in Chapter 8; logged out, the request is
now rejected with a 401 instead.

THE EXACT LINE RESPONSIBLE
------------------------------
Per this chapter, the responsible lines are:

  const session = await getSession(request);
  if (!session) {
    return new Response(null, { status: 401 });
  }

added at the very top of the endpoint in Chapter 9 - they did not
exist at all in Chapter 8's own version.

WHY THIS WORKS AS AN ANSWER
------------------------------
It correctly identifies that the surrounding code is unchanged since
Chapter 8, and correctly identifies the added getSession() check -
absent in Chapter 8, present since Chapter 9 - as the exact
difference responsible for the request now being genuinely protected.