docs: gotcha 48, and the gh graphql workaround

The browser JavaScript is argued, not tested, and the two rules it can break
are both about WHEN: an async message listener does not serialize, and a
watchdog must be disarmed rather than pre-empted. Both found by review
rather than by a test, because nothing here runs a browser.

Plus the third thing no test can see: three comments in one range said 'not
built yet' about work that landed in that same range, each because a
follow-up commit updated one copy of an argument and not its siblings.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EoW5BB87ZZdm96SvBTWawH

context/repo-map.md

@@ -250,6 +250,10 @@ Region=West, Measure=Revenue = |pending|   # pipe-quoted text
 
     Two corrections to the ticket's own gap list, both worth more than the code. **Panel cursor movement was never a gap**: improvise-edp had already made `viewmodel::flatten_cat_tree` the one home both ends call, so it is the *shared* derivation, not a second one — worth re-checking the "known gaps" in other old tickets against what has landed since. And the "unmodified characters only" rule was **mis-scoped, not wrong**: it was about `KeyPattern::AnyChar`, which is bound only in the text-entry modes, so `Ctrl-d` in Normal has an exact binding and mirroring it is a faithful subset. Each resolver mirrors its `Cmd` **line for line, including where siblings disagree** — `Move` and `MoveTileCursor` emit even when they clamp, `MovePanelCursor` returns nothing when the cursor does not move. Tidying that into one rule would make the client a second derivation, which is what `tests/lockstep.rs` exists to rule out. What still needs the host is a **named list** in `keys.rs` and in `the_normal_mode_keys_that_still_need_the_host_are_these`, so closing one has to come there and say so.
 
+48. **The browser JavaScript is argued, not tested, and the two rules it can break are both about *when*.** There is no browser and no headless DOM here, so `web/app.js` and `web/worker.js` are syntax-checked, `.d.ts`-checked for call arity, and read — never executed. Two classes of bug follow, both found by review rather than by a test. **An `async` `message` listener does not serialize.** `worker.js`'s `handle()` awaits `server.flush()`, so the event loop may start the next message while an earlier one is suspended, interleaving two `on_message`/`flush` pairs and letting a later frame's replies **overtake** an earlier frame's — which gotcha 33 answers by *dropping* the overtaken update, not by replaying it. Every frame is therefore chained onto **one tail promise** and the listener is deliberately not `async`; that also turns "frames that arrived before `start()` finished" into an ordinary case of the ordering rule instead of a drain loop, which had the same race twice over because `server` was assigned *before* the loop ran. **A watchdog must be disarmed, not pre-empted.** The handshake watchdog exists for one condition — the peer never answered — and every *loud* failure (worker `error`/`messageerror`, socket `error`) has already written something more precise; the timer then fired 8s later and replaced it, so `setShellFailure` clears it. Its unfixed neighbour is the socket's `close` listener, which still overwrites an `error` with "disconnected" (improvise-m18f) — and that one is *not* the same fix, because suppressing `close` could hide a genuine mid-session disconnect.
+
+    **A third thing no test here can see, which is why the docs must be read as code.** Three comments in one range said "not built yet" about work that had landed *in that same range* — `README.md`'s browser section, `app.js`'s keyboard note, and `Host::handle`'s `Key` arm — each because a follow-up commit updated **one copy of an argument and not its siblings**. When a fact is stated in more than one place, changing it is a grep, not an edit.
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 ## File Inventory