An admin area a phone could reach and not navigate

Administration has a nav of its own rather than the chat sidebar, and 1.1.0
gave every `.sidebar` the drawer behaviour -- starts closed, slides in --
without giving that one any of the drawer's furniture. No id for the toggle to
resolve, no toggle, no close, no scrim: it sat at left:-280 with nothing in the
application able to open it. The close button and the scrim are partials now,
used by both, and the test that guards it *finds* sidebars by scanning the
templates rather than working from a list, which is exactly why this one was
missed.

The chat, measured at 390px, spent forty pixels of side padding and a
forty-four pixel avatar column before drawing a word -- close to a quarter of
the screen on margin, so anything that could not wrap had to be reached
sideways. Padding halved and the avatar moved above the turn; a code block
gained about sixty pixels.

Worse in the same row: `.topbar__actions` asked for 317px of a 390px bar,
because the control that used to give in that row is display:none below a
tablet width, so the group went rigid and the title -- flex: 1 -- was squeezed
to exactly zero. And `.btn--icon` sets a width with no `flex: none`, so the row
shrank the button instead of the text: the sidebar toggle measured eighteen
pixels across. The picker gives now, and shows its avatar rather than its name
on a phone.

Also the instrument, which lied twice more: it could not see horizontal
overflow at all, because `.shell` is overflow:hidden and its "is this
contained" test therefore answered yes for everything on the page; and run from
a copy it resolved `STATIC` to a directory that did not exist, rewrote every
asset URL to a dead file:// path and reported the whole application overflowing
by thirty thousand pixels. It resolves from the imported package now and
asserts that what it rewrote to is really there.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/shoot.py

@@ -29,10 +29,19 @@ import tempfile
 from pathlib import Path
 
 REPO = Path(__file__).resolve().parent.parent
-SRC = REPO / "src"
-sys.path.insert(0, str(SRC))
+sys.path.insert(0, str(REPO / "src"))
 
-STATIC = SRC / "lembas/web/static"
+# Resolved from the package that actually got imported, not from where this
+# file happens to sit. A copy of this script run from somewhere else silently
+# pointed STATIC at a directory that did not exist, every asset URL was
+# rewritten to a file:// path with nothing behind it, and the run measured an
+# unstyled document -- reporting that every page in the application overflowed
+# by thirty thousand pixels. The guard below only asked whether the URLs had
+# been rewritten, which they had.
+import lembas  # noqa: E402
+
+SRC = Path(lembas.__file__).resolve().parent.parent
+STATIC = Path(lembas.__file__).resolve().parent / "web/static"
 CHROMIUM = shutil.which("chromium") or shutil.which("chromium-browser")
 
 # Routes that are served by the app rather than mounted, so the rewrite has to
@@ -131,8 +140,17 @@ window.__measure = function () {
     tallCulprits: culprits('y'),
     wideCulprits: culprits('x'),
     /* The invariant: the application shell fills the window and the DOCUMENT
-       never scrolls. A document taller than the window is the /settings bug. */
-    documentScrolls: de.scrollHeight > window.innerHeight + 1,
+       never scrolls *for the reader*. A document taller than the window is the
+       /settings bug -- but only when the reader can actually move it. `overflow:
+       hidden` blocks a wheel and a finger while still permitting an assignment
+       to scrollTop, so a page whose shell clips a tall descendant reports a
+       scrollHeight of thousands and scrolls for nobody. /admin/prompts does
+       exactly that, and reading the raw height called it a bug four times. */
+    documentScrolls:
+      de.scrollHeight > window.innerHeight + 1 &&
+      ["visible", "auto", "scroll"].indexOf(
+        getComputedStyle(document.documentElement).overflowY
+      ) !== -1,
     scrollsSideways: de.scrollWidth > window.innerWidth + 1,
     smallTargets: small.slice(0, 40),
     smallCount: small.length,
@@ -219,6 +237,18 @@ def rewrite(html: str, client, assets: Path) -> str:
             f"{sorted(set(blocking))[:8]}"
         )
 
+    # And that what they were rewritten *to* is really there. A rewrite that
+    # matches and produces a dead path is indistinguishable, from inside the
+    # browser, from no stylesheet at all -- and it is the failure that actually
+    # happened, twice.
+    missing = [
+        url
+        for url in re.findall(r'(?:href|src)="file://([^"?]+)"', html)
+        if not Path(url).exists()
+    ]
+    if missing:
+        raise SystemExit(f"REWRITTEN TO NOTHING -- still an unstyled document: {missing[:5]}")
+
         # The one-time notifications offer is a modal over the very page we came
     # to measure, and it is gated on a localStorage key. Set it in the head, so
     # it runs before the deferred script that reads it.