feat(ui): in-app FAQ, DPI-scaling audit fixes, mining/stratum polish + localize strings

Bundles the session's UI work (the touched files carry several of these
changes together, so they are committed as one coherent UI batch):

- FAQ: new RenderFaqDialog + data-driven faq_content, opened from a
  status-bar "?" (and the Windows title bar), styled like the Wallets
  modal with search, Wallet/Daemon tabs, and smooth scroll.
- DPI/font-scale audit: multiply hand-drawn absolute geometry by
  Layout::dpiScale() across ~30 files so nothing renders native-size at
  HiDPI / font_scale 1.5 (verified with a full sweep at 1.5x).
- Mining: chart now fills the horizontal space; thread stepper +/- buttons
  match the input-box height; move the stratum-host toggle into
  Node & Security (v1.3.0+).
- Settings: fix the auto-shield status text overlapping the grid.
- Sidebar: drop the peer-count badge on the Network button.
- i18n: wrap 193 hardcoded literals with TR() (keys/translations added in
  the preceding i18n commit), so the security/PIN/lock flow, seed-backup
  wizard, and witness-rebuild dialog localize.

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

src/ui/windows/explorer_tab.cpp

@@ -108,13 +108,13 @@ static const char* relativeTime(int64_t timestamp) {
     int64_t diff = now - timestamp;
     if (diff < 0) diff = 0;
     if (diff < 60)
-        snprintf(buf, sizeof(buf), "%lld sec ago", (long long)diff);
+        snprintf(buf, sizeof(buf), TR("grpa_sec_ago"), (long long)diff);
     else if (diff < 3600)
-        snprintf(buf, sizeof(buf), "%lld min ago", (long long)(diff / 60));
+        snprintf(buf, sizeof(buf), TR("grpa_min_ago"), (long long)(diff / 60));
     else if (diff < 86400)
-        snprintf(buf, sizeof(buf), "%lld hr ago", (long long)(diff / 3600));
+        snprintf(buf, sizeof(buf), TR("grpa_hr_ago"), (long long)(diff / 3600));
     else
-        snprintf(buf, sizeof(buf), "%lld days ago", (long long)(diff / 86400));
+        snprintf(buf, sizeof(buf), TR("grpa_days_ago"), (long long)(diff / 86400));
     return buf;
 }
 
@@ -1216,7 +1216,7 @@ static void renderBlockDetailModal(App* app) {
                 txDL->AddRectFilled(rowStart,
                     ImVec2(rowStart.x + txContentW, rowStart.y + txRowH),
                     WithAlpha(OnSurface(), 10),
-                    S.drawElement("tabs.explorer", "row-rounding").size);
+                    S.drawElement("tabs.explorer", "row-rounding").size * dp);
                 ImGui::SetMouseCursor(ImGuiMouseCursor_Hand);
                 material::Tooltip("%s", txid.c_str());
             }
@@ -1315,7 +1315,7 @@ static void renderBlockDetailModal(App* app) {
         }
 
         if (s_detail_txids.size() > 100) {
-            snprintf(buf, sizeof(buf), "... showing first 100 of %d", (int)s_detail_txids.size());
+            snprintf(buf, sizeof(buf), TR("grpa_showing_first_100_of"), (int)s_detail_txids.size());
             ImGui::TextDisabled("%s", buf);
         }
     }