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/wallets_dialog.h

@@ -100,7 +100,7 @@ public:
         const float headH   = Type().h6()->LegacySize + Layout::spacingXs()      // framework h6 title
                             + Type().caption()->LegacySize + Layout::spacingSm()   // intro + gap
                             + ctrlRow + Layout::spacingSm();                       // sort control row + gap
-        const float padV    = 48.0f;                                             // content-child padding (top+bottom) + margin
+        const float padV    = 48.0f * dp;                                        // content-child padding (top+bottom) + margin
         // Size to content, but cap at a viewport fraction: with many wallets on a small / HiDPI
         // screen the content-sized card could exceed the window (the framework would clip a too-tall
         // card, footer and all). When capped, the wallet list flexes + scrolls and the controls