mobile: per-view ≤480px rules across the CSS bundle

Adds the @media (max-width: 480px) blocks specified in the design:

- dashboard.css: indicator table hides the 'mobile-hide'-tagged
  columns (Label, Ccy, 1y, anchor, as-of), keeping Symbol / Price /
  1d / 1m. Cell padding + font shrink. Group-tab buttons get a
  bigger touch target.
- panels.css: header padding tightens, scroll-body max-height drops
  to 60vh so log/news stay above the fold in the stacked layout.
- portfolio.css: overall grid keeps 2 cols (already at 640px) with
  tighter gap; action buttons wrap; composer input goes full-width.
- log-chat.css: chat bubbles edge-to-edge, input row stacks, font-
  size:14px on form fields to avoid iOS Safari zoom-on-focus.
- news.css: row collapses to age | (title / source) — source moves
  under the title. Tag filter strip wraps.
- settings.css: form rows stack (label above input). Import picker
  becomes single-column. Buttons full-width.
- auth.css: card padding tightens to free up vertical space when the
  iOS keyboard is up. font-size:14px on inputs.
- public.css: hero headline clamp() lower bound drops to 22px; CTAs
  stack full-width; pricing tier-grid stacks.

indicators.html: tagged the secondary cells with .mobile-hide rather
than relying on positional nth-child — the anchor column is
conditional and would have shifted positions.

336 tests still pass.

app/static/css/settings.css

@@ -379,3 +379,38 @@
   box-sizing: border-box;
 }
 .modal-input:focus { border-color: var(--accent); }
+
+
+/* --- Mobile (≤480px) -------------------------------------------------- */
+
+@media (max-width: 480px) {
+  /* Form rows stack: label above value instead of side-by-side. The
+     desktop layout uses a fixed 110px label column that pinches the
+     value column unbearably on a phone. */
+  .settings-row {
+    flex-direction: column;
+    align-items: stretch;
+    gap: 4px;
+    padding: 10px 0;
+  }
+  .settings-row__label {
+    width: auto;
+    font-size: 11px;
+    text-transform: uppercase;
+    letter-spacing: 0.06em;
+  }
+  .settings-select {
+    width: 100%;
+    font-size: 14px;     /* avoids iOS Safari zoom-on-focus */
+  }
+
+  /* The two-column import picker becomes single column. */
+  .import-choice {
+    flex: 1 1 100%;
+    min-width: 0;
+  }
+
+  /* Buttons get a full-width tap target. */
+  .settings-btn { width: 100%; padding: 10px; }
+  .settings-icon-btn { width: 100%; justify-content: center; }
+}