feat(ui): layout polish — fill dead space, pair/box/collapse, warning weight, dialog glass

Implements the layout-improvement suggestions from the layout audit (visual arrangement
only; no functionality added or removed):

- Send/Receive: the recent-activity list now grows to fill the space below the fixed
  compose/receive card (more history visible), with a centered empty-state when there is
  none — instead of leaving dead canvas.
- Shield/Merge: pair the Fee and UTXO-Limit fields on one row to tighten vertical rhythm.
- Market: extend + frame the portfolio group-list as one contained panel (with a bottom
  edge) and center its empty-state, closing the previously un-anchored gap.
- Overlay dialogs: raise the card glass fill/border alpha (35/50 -> 60/90 of 255) so the
  dialog card reads as a distinct surface over busy backdrops (global, all overlays).
- Wallets: size the list height to the actual wallet count instead of always reserving 7
  rows, removing the large gap before the scan/create prompts (still scrolls when many).
- Contacts: width-aware address truncation shows more of the address on wide rows.
- Transfer Funds: give the "sends the full balance" warning a warning icon + color so the
  stakes stand out from the neutral result-preview lines.
- First-run wizard: collapse a completed Step 1 (Appearance) to the compact pill like
  Step 2, so a finished step is no longer taller than the active one.
- Explorer: distribute the Chain card's two stats to match the density of the sibling
  metrics grid.
- Validate Address: a "Results will appear here" caption fills the pre-interaction blank.
- Change Passphrase: add the warning banner its sibling security dialogs have.
- Migration ShowSeed: box the 24-word mnemonic grid (a GlassSectionScope behind the
  existing RenderSeedWordGrid) so the critical secret reads as a distinct artifact —
  purely visual, no seed/logic/state change.

Verified at 1280 across full-node + Lite + Windows (ctest green) and an adversarial diff
review (clean). New i18n key backfilled into all 8 languages.

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

src/ui/windows/wallets_dialog.h

@@ -71,9 +71,12 @@ public:
         const int   kMaxVisibleRows = 7;
         ImFont* nameFont = Type().subtitle1();
         ImFont* metaFont = Type().caption();
-        // The list is always sized to its MAX height (kMaxVisibleRows) for a consistent modal size — it
-        // does not shrink to fit a few wallets; fewer rows leave empty space, more than 7 scroll.
-        const int   visRows  = kMaxVisibleRows;
+        // Size the list to the ACTUAL wallet count so a few wallets sit tight against the controls below
+        // instead of stranding ~200px of empty rows before the create/scan prompts; cap at kMaxVisibleRows
+        // (more than that scrolls within the cap). An empty list keeps two rows of height so the centered
+        // empty-state hint (drawn inside the list child) still has room to show.
+        const int   numWallets = (int)s_rows.size();
+        const int   visRows  = numWallets <= 0 ? 2 : std::min(numWallets, kMaxVisibleRows);
         const float cardPadY = Layout::spacingMd();   // roomier cards (was spacingSm)
         const float walRowH  = cardPadY * 2.0f + nameFont->LegacySize + Layout::spacingSm() + metaFont->LegacySize;
         const float cardGap  = Layout::spacingMd();   // more breathing room between wallet cards
@@ -421,9 +424,10 @@ public:
                 ImGui::Dummy(ImVec2(rowW, walRowH));
                 if (i + 1 < s_rows.size()) ImGui::Dummy(ImVec2(rowW, cardGap));
             }
-            // Empty-state nudge: the list sits at a fixed max height, so a handful of wallets leave blank
-            // space below. When there's real room to spare, fill it with a subtle centered hint (a folder
-            // glyph + one line) instead of dead space; it's purely decorative — the actions live below.
+            // Empty-state nudge: the list is now sized to the actual wallet count, so a populated list has
+            // no room to spare and this draws nothing (the cards butt up against the controls below). It
+            // fires only when the list is EMPTY (the reserved rows leave room): a subtle centered hint (a
+            // folder glyph + one line) instead of a blank box; purely decorative — the actions live below.
             {
                 const float remainY = ImGui::GetContentRegionAvail().y;
                 if (remainY > walRowH * 1.6f) {