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/mining_earnings.cpp

@@ -220,7 +220,7 @@ void RenderMiningEarnings(App* app, const WalletState& state, const MiningInfo&
             if (estActive)
                 snprintf(estVal, sizeof(estVal), "~%.4f", estDaily);
             else
-                snprintf(estVal, sizeof(estVal), "N/A");
+                snprintf(estVal, sizeof(estVal), "%s", TR("grpc_na"));
             // Disclose in pool mode that Est. Daily is a rough solo-equivalent (before the pool fee), so the
             // number isn't silently mismatched to its plain "Est. Daily" label. (M-05)
             const char* estSub = (s_pool_mode && estActive) ? TR("mining_est_daily_pool_sub") : nullptr;
@@ -475,7 +475,7 @@ void RenderMiningEarnings(App* app, const WalletState& state, const MiningInfo&
             else if (totalRAM > 0)
                 snprintf(sysBuf, sizeof(sysBuf), "-- / %.0f GB", totalRAM / 1024.0);
             else
-                snprintf(sysBuf, sizeof(sysBuf), "N/A");
+                snprintf(sysBuf, sizeof(sysBuf), "%s", TR("grpc_na"));
 
             float sysTextW = capFont->CalcTextSizeA(capFont->LegacySize, 10000, 0, sysBuf).x;
             float sysTextX = barX + barW - textPadX - sysTextW;