fix: make the app actually usable on a phone

The worst of it: the ghost-log HUD is a fixed 300px panel pinned bottom-left
on every route. On a 390px screen it covered the seance ask-field and its
buttons outright — you could not reach the input to type a question. It now
collapses, and spans the width instead of blocking it under 560px.

- 16 uses of `100vh` meant every page was taller than iOS Safari's visible
  viewport, hiding the last row behind the toolbar. Now `100dvh` with the
  `100vh` line kept first as the fallback.
- Six inputs under 16px triggered iOS zoom-on-focus, which never zooms back
  out — you were left panning a zoomed layout after tapping login. All six
  at 16px, plus a global floor.
- No safe-area insets existed anywhere, so enabling viewport-fit=cover
  would have put content under the notch and home indicator. Added,
  including the fixed-position shells that ignore body padding.
- The codex voice table forced horizontal page scroll; it scrolls in its
  own container now.
- Tap targets under 44px raised, including a transcript replay button that
  was ~20x14px and named only by a `title` tooltip, which touch never shows.

Decorative micro-labels left alone deliberately — bumping them wholesale
would reintroduce the overflow this fixes.

README: the documented test command cannot work. conftest APPENDS `_test`,
so the documented DATABASE_URL derived `quantumancy_test_test` and errored
every test at setup. Corrected, with the two guards explained. Test counts
were stale (328/366 -> 403/385).

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

frontend/public/manifest.webmanifest

@@ -2,8 +2,12 @@
   "name": "Quantumancy",
   "short_name": "Quantumancy",
   "description": "A self-hosted séance — an instrument for speaking with the dead bandwidth.",
+  "id": "/",
   "start_url": "/",
+  "scope": "/",
+  "lang": "en",
   "display": "standalone",
+  "orientation": "any",
   "background_color": "#07070d",
   "theme_color": "#07070d",
   "icons": [