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/material/draw_helpers.h

@@ -925,7 +925,7 @@ inline void DrawStatCard(ImDrawList* dl,
     //    Draw a full-height rounded rect with card rounding (left corners)
     //    and clip to stripe width so the shape follows the corner radius.
     if ((card.accentCol & IM_COL32_A_MASK) != 0) {
-        float stripeW = 4.0f;
+        float stripeW = 4.0f * Layout::dpiScale();
         dl->PushClipRect(cMin, ImVec2(cMin.x + stripeW, cMax.y), true);
         dl->AddRectFilled(cMin, cMax, card.accentCol, rnd,
                           ImDrawFlags_RoundCornersLeft);
@@ -1282,7 +1282,8 @@ inline bool DrawDialogTitleBar(const char* title, bool* p_open, ImU32 accent_col
     ImDrawList* dl = ImGui::GetWindowDrawList();
     ImVec2 winPos = ImGui::GetWindowPos();
     float winWidth = ImGui::GetWindowWidth();
-    float barHeight = 36.0f;
+    const float dp = Layout::dpiScale();
+    float barHeight = 36.0f * dp;
     
     // Get accent color from theme if not provided
     if (!accent_col) {
@@ -1306,15 +1307,15 @@ inline bool DrawDialogTitleBar(const char* title, bool* p_open, ImU32 accent_col
     ImFont* titleFont = Type().subtitle1();
     ImGui::PushFont(titleFont);
     ImVec2 titleSize = ImGui::CalcTextSize(title);
-    float titleX = barMin.x + 16.0f;
+    float titleX = barMin.x + 16.0f * dp;
     float titleY = barMin.y + (barHeight - titleSize.y) * 0.5f;
     DrawTextShadow(dl, ImVec2(titleX, titleY), OnSurface(), title);
     ImGui::PopFont();
     
     // Close button (X) on right side
     if (p_open) {
-        float btnSize = 24.0f;
-        float btnX = barMax.x - btnSize - 12.0f;
+        float btnSize = 24.0f * dp;
+        float btnX = barMax.x - btnSize - 12.0f * dp;
         float btnY = barMin.y + (barHeight - btnSize) * 0.5f;
         ImVec2 btnMin(btnX, btnY);
         ImVec2 btnMax(btnX + btnSize, btnY + btnSize);
@@ -1327,7 +1328,7 @@ inline bool DrawDialogTitleBar(const char* title, bool* p_open, ImU32 accent_col
         
         // Button background on hover
         if (hovered) {
-            dl->AddRectFilled(btnMin, btnMax, IM_COL32(255, 255, 255, held ? 40 : 25), 4.0f);
+            dl->AddRectFilled(btnMin, btnMax, IM_COL32(255, 255, 255, held ? 40 : 25), 4.0f * dp);
         }
         
         // Draw X icon
@@ -1348,7 +1349,7 @@ inline bool DrawDialogTitleBar(const char* title, bool* p_open, ImU32 accent_col
     }
     
     // Reserve space for title bar so content starts below it
-    ImGui::SetCursorPosY(ImGui::GetCursorPosY() + barHeight + 8.0f);
+    ImGui::SetCursorPosY(ImGui::GetCursorPosY() + barHeight + 8.0f * dp);
     
     return closeClicked;
 }
@@ -1648,7 +1649,7 @@ inline bool BeginOverlayDialog(const OverlayDialogSpec& spec)
         // Fill/border alpha govern every overlay dialog's card boundary — kept well above the default
         // glass panel so the card reads as a distinct surface over busy backdrops (tx lists, mining
         // tiles, chat) while staying translucent rather than opaque.
-        cardGlass.rounding = 16.0f; cardGlass.fillAlpha = 60; cardGlass.borderAlpha = 90; cardGlass.borderWidth = 1.0f;
+        cardGlass.rounding = 16.0f * dp; cardGlass.fillAlpha = 60; cardGlass.borderAlpha = 90; cardGlass.borderWidth = 1.0f;
         DrawGlassPanel(dl, cardMin, cardMax, cardGlass);
     }
 
@@ -1662,8 +1663,8 @@ inline bool BeginOverlayDialog(const OverlayDialogSpec& spec)
 
     // Content child.
     ImGui::SetCursorScreenPos(ImVec2(cardX, cardY));
-    ImGui::PushStyleVar(ImGuiStyleVar_ChildRounding, floating ? 20.0f : 16.0f);
-    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, floating ? ImVec2(28, 20) : ImVec2(28, 24));
+    ImGui::PushStyleVar(ImGuiStyleVar_ChildRounding, floating ? 20.0f * dp : 16.0f * dp);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, floating ? ImVec2(28 * dp, 20 * dp) : ImVec2(28 * dp, 24 * dp));
     ImGui::PushStyleColor(ImGuiCol_ChildBg, ImVec4(0, 0, 0, 0));  // transparent (glass/blur behind)
     // A card with a known height is a fixed frame (fixed-height dialogs, and auto-height dialogs whose
     // content overflowed the viewport); otherwise the child auto-resizes to its content.