fix: final review findings

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

course/09-wiring-it-together.md

@@ -229,11 +229,11 @@ Remember section 12 of Module 7: the loop only helps if each continuation does a
 That's the whole runtime. Go back to the stateful code at the start of Module 8, with its `let state` and logic in callbacks, and compare. There, the mutable variable held the *game state*, and game logic lived in the callbacks. Here, the variable holds the *current stream* — the runtime doesn't even know there's a game. It has no idea what a snake, a tick or a score is. All the game logic is in pure values; the runtime is a few lines of plumbing. That is what "pushing effects to the edge" means in practice.
 
 ```
-                 ┌──────────────────────── runtime (impure, ~20 lines) ─────────────────────────┐
- browser ──key──▶│ feed(KeyDown key):  [ios, next] = stream.step(ev); stream = next; ios.forEach(runIO) │──▶ canvas
-         ──time─▶│ feed(Time t)                                                                  │
-                 └───────────────────────────────────────────────────────────────────────────────┘
-                                  ▲ the one `let` / `var` / ref cell: stream
+                 ┌────────────────────────────── runtime (impure, ~20 lines) ─────────────────────────────────┐
+ browser ──key──▶│ feed(KeyDown key):  [ios, next] = stream.step(ev); stream = next; ios.forEach(runIO)       │
+         ──time─▶│ feed(Time t)                                                                               │
+                 └────────────────────────────────────────────────────────────────────────────────────────────┘
+                 ▲ the one `let` / `var` / ref cell: stream
 ```
 
 The tests describe the behaviour precisely; read them before writing the code: