feat(machine): add markdown-driven support pages

Add support/help pages accessible via a ? button on the idle screen.
Pages are driven by .md files in /var/lib/lamassu-atm/support/ —
operators can customize content without rebuilding the app.

Features:
- Tabbed view with markdown rendering (via marked)
- Standalone URLs auto-render as QR codes (scannable from phone)
- Table URLs: click-to-reveal QR codes (prevents accidental scans)
- Yes/No rendered as green checkmarks / red X marks
- Wallet comparison table with download QR codes
- FAQ with Lightning-only clarification
- Support page with operator Nostr QR placeholder
- Custodial vs non-custodial footnote
- Large text for touchscreen accessibility
- Centered layout for short-content pages

Closes #36

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

nix/mkAtmApp.nix

@@ -38,7 +38,7 @@ pkgs.stdenv.mkDerivation (finalAttrs: {
     inherit (finalAttrs) pname version src pnpmWorkspaces;
     inherit pnpm;
     fetcherVersion = 3;
-    hash = "sha256-Y6VCaGDHDqhx8PN4rgpDI0EWEy+6oCaSnotODPK+310=";
+    hash = "sha256-Jv5p62E40DtCSZvN/+LTzkhRYJBTyyUOVSBlQyxzcEw=";
   };
 
   nativeBuildInputs = [