refactor(ui): consolidate dialog footers + shared empty-state, unify buttons/rounding

Addresses the cross-screen inconsistencies from the layout audit by routing screens onto
the design system's own (previously under-used) shared helpers:

- Dialog footers: migrate ~9 overlay dialogs off hand-rolled placement onto the shared
  helpers — DialogActionFooter (primary+Close), DialogConfirmFooter, or
  BeginOverlayDialogFooter for custom/multi-button rows — so footers share one centered
  treatment. All footer/action buttons now use TactileButton (glass press) instead of the
  bare StyledButton some dialogs used.
- Empty states: add a shared material::DrawEmptyState(icon, title, hint) (centered icon +
  title + wrapped hint) and adopt it in Peers, Transactions, and Market-portfolio, which
  previously showed a bare left-aligned caption.
- Security dialogs: add the missing Cancel to Change Passphrase and Set PIN so the whole
  security family shares a two-button footer (Cancel dismisses without applying).
- Transactions pager: shared TactileButton helpers (matching Explorer).
- Frosted-pane rounding: Contacts/Chat use Layout::glassRounding() instead of hardcoded
  12/10/8px literals, matching Peers.
- "Set Label..." title loses its stray trailing ellipsis.

Preserves every button's label and action; the transfer footer's order becomes
[Confirm][Cancel] to match the shared helper's primary-first convention. Verified at 1280
across full-node + Lite + Windows (ctest green) and an adversarial diff review (clean).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/shield_dialog.cpp

@@ -184,9 +184,16 @@ void ShieldDialog::render(App* app)
         bool sh_syncing   = state.sync.syncing;
         bool can_submit = !s_operation_pending && s_to_address[0] != '\0' && sh_connected && !sh_syncing;
 
-        if (!can_submit) ImGui::BeginDisabled();
-        
+        // Center the primary + Cancel action row via the shared footer helper. We can't use
+        // DialogActionFooter here because the primary button carries a disabled-hover tooltip that must
+        // fire on ITS item (the helper draws primary+Close internally, leaving no hook between them), so
+        // we keep the two TactileButtons + the interleaved tooltip and only standardize the placement.
         const char* btn_label = (s_mode == Mode::ShieldCoinbase) ? TR("shield_funds") : TR("merge_funds");
+        float footerBtnW = shieldBtn.width + cancelBtn.width + ImGui::GetStyle().ItemSpacing.x;
+        material::BeginOverlayDialogFooter(footerBtnW, /*drawSeparator=*/false);
+
+        if (!can_submit) ImGui::BeginDisabled();
+
         if (material::TactileButton(btn_label, ImVec2(shieldBtn.width, 0), S.resolveFont(shieldBtn.font))) {
             s_operation_pending = true;
             s_status_message = TR("shield_submitting");