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/market_tab.cpp

@@ -1580,7 +1580,7 @@ static void mktDrawPriceHero(const MktCtx& cx)
         }
     } else {
         const char* status = market.price_loading ? TR("market_price_loading") : TR("market_price_unavailable");
-        DrawTextShadow(dl, sub1, sub1->LegacySize, ImVec2(cx0, cy + 10), OnSurfaceDisabled(), status);
+        DrawTextShadow(dl, sub1, sub1->LegacySize, ImVec2(cx0, cy + 10 * dp), OnSurfaceDisabled(), status);
         if (!market.price_loading && !market.price_error.empty()) {
             std::string errorText = market.price_error;
             float maxErrorW = cardMax.x - cx0 - Layout::spacingLg();
@@ -1590,7 +1590,7 @@ static void mktDrawPriceHero(const MktCtx& cx)
             }
             if (errorText.size() < market.price_error.size()) errorText += "...";
             dl->AddText(capFont, capFont->LegacySize,
-                        ImVec2(cx0, cy + 10 + sub1->LegacySize + Layout::spacingXs()),
+                        ImVec2(cx0, cy + 10 * dp + sub1->LegacySize + Layout::spacingXs()),
                         Warning(), errorText.c_str());
         }
     }
@@ -1874,7 +1874,7 @@ static void mktDrawPriceChart(const MktCtx& cx)
                          : (tk == ticks - 1)    ? plotRight - lblSz.x
                                                 : xpos - lblSz.x * 0.5f;
                 dl->AddText(capFont, capFont->LegacySize,
-                            ImVec2(lx, plotBottom + 4), OnSurfaceDisabled(), tlbl);
+                            ImVec2(lx, plotBottom + 4 * mktDp), OnSurfaceDisabled(), tlbl);
             }
         }