fix(as-S5a): every control named, one h1 and a skip link, rings and hit areas

The markup and CSS half of the anti-slop interaction work. The in-place
client is untouched (that is S5b).
- Glyph-only controls carry a name: the withdraw ×s, downloads, open full
  page, the viewers' ✕, the board's pin, copy and remove, the bench's
  remove, the 1:1 toggle ("1:1, natural pixels"). Film-strip and tray
  frames carry the file's name as sr-only text instead of reading "01".
  A Desk row's wipe names its booth.
- Fields are named by aria-label, not by their placeholder.
- The inline ask's options are a radiogroup labelled by the prompt; a
  single-question fieldset gets an sr-only legend; a titled ask's title
  takes bk-ask-<id>-title (it duplicated the question's id).
- One h1 per page (sr-only on the Desk, review and compare), a skip link
  to <main id="main">, theme-color for light and dark.
- The review tape is one picture (role=img); its segments leave the tab
  order (the film strip holds the same links, named).
- Wipe now uses the Desk's delegated prompt, moved to base.html: it names
  the booth and asks the kept-booth question for a kept booth.
- Embed focus rings of its own; rings drawn inside clipping containers;
  the withdraw × at least 24px, 44px under a coarse pointer;
  touch-action:manipulation; strips contain their overscroll; a long
  slug wraps on a phone.
- A truncated why carries its full text in title; a countdown of 48h or
  more reads in days.
Two r2_flow.toml rows for the confirm helper now name base.html, where
the helper moved (anchors unchanged; the gate found them drifted).

Contract: as_antislop S5a. Falsifiers: antislop.toml 86/86 proved (S1-S6, S5a);
all 12 tables 366/366 proved on this tree.

booth/app.py

@@ -231,6 +231,11 @@ def human_dur(seconds: float) -> str:
         return "expired"
     h, rem = divmod(s, 3600)
     m, _ = divmod(rem, 60)
+    # as S5a: past two days the hours roll up ("6d 23h", not "167h 12m"); the
+    # minutes are noise at that range. Under 48h the hours stay, as before.
+    if h >= 48:
+        d, h = divmod(h, 24)
+        return f"{d}d {h}h" if h else f"{d}d"
     if h and m:
         return f"{h}h {m}m"
     if h: