fix(ui): scale unscaled geometry at HiDPI — inputs, send progress cards, chat/pool overlaps, peer rows

At font_scale 1.5 ~13 sites read absolute geometry (schema .size/.width) straight
into ImGui without ×dpiScale(), so they stayed native-size while the font grew and
overlapped/clipped real text or money:

- Shield/Merge fee + UTXO inputs, Request Payment amount, Block Info height input:
  ×dpiScale() so the value no longer clips (e.g. 0.00010000 -> 0.00010).
- Send: the confirm-popup Amount Details divider (floored the row step at the scaled
  caption height so it no longer strikes the Fee row), the tx-progress error and
  sending/success cards, and the zero-balance CTA button — all ×dp.
- Mining pool row: ellipsis-truncate the hostname so it can't collide with the
  right-aligned hashrate.
- Chat conversation list: scale the pane-width clamp AND clip the peer name to the
  column left of the timestamp (measure-then-clip) so name and time never overlap.
- Explorer block-detail label column, Peers row offsets, and DialogConfirmFooter
  button height — ×dp.

transaction_details keeps its negative fill-sentinel widths unscaled (a content
margin, not raw px). Verified at font_scale 1.5 across full-node + Lite + Windows
(ctest green) and an adversarial diff review (three wrong-scale regressions fixed).

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

src/ui/windows/shield_dialog.cpp

@@ -148,7 +148,7 @@ void ShieldDialog::render(App* app)
 
         // Fee
         ImGui::Text("%s", TR("fee_label"));
-        ImGui::SetNextItemWidth(feeInput.width);
+        ImGui::SetNextItemWidth(feeInput.width * Layout::dpiScale());
         ImGui::InputDouble("##Fee", &s_fee, 0.0001, 0.001, "%.8f");
         if (s_fee < 0.0) s_fee = 0.0;          // no negative fee
         if (s_fee > 1.0) s_fee = 1.0;          // guard a fat-fingered huge fee (mirrors utxo clamp)
@@ -159,7 +159,7 @@ void ShieldDialog::render(App* app)
 
         // UTXO limit
         ImGui::Text("%s", TR("shield_utxo_limit"));
-        ImGui::SetNextItemWidth(utxoInput.width);
+        ImGui::SetNextItemWidth(utxoInput.width * Layout::dpiScale());
         ImGui::InputInt("##Limit", &s_utxo_limit);
         ImGui::SameLine();
         ImGui::TextDisabled("%s", TR("shield_max_utxos"));