feat: system settings, dynamic logos, template numbering, permission consolidation

- System settings page with tabs: Security, System, Firma
- Configurable attendance rules (break thresholds, rounding) from DB
- Configurable document numbering with template patterns ({YYYY}/{PREFIX}/{NNN})
- Dynamic logo upload (light/dark variants) served from DB instead of static files
- Email settings (SMTP from/name, alert/leave emails) configurable in UI
- Currency and VAT rate lists configurable, used across all modules
- Permissions simplified: offers.settings + settings.roles + settings.security → settings.manage
- Leaflet bundled locally, removed unpkg.com from CSP
- Silent catch blocks fixed with proper logging
- console.log replaced with app.log.info in server.ts
- Schema renamed: company-settings.schema → settings.schema
- App info section: version, Node.js, uptime, memory, DB status, NAS status

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

src/admin/pages/Login.tsx

@@ -190,11 +190,17 @@ export default function Login() {
               <img
                 src={
                   theme === "dark"
-                    ? "/images/logo-dark.png"
-                    : "/images/logo-light.png"
+                    ? "/api/admin/company-settings/logo?variant=dark"
+                    : "/api/admin/company-settings/logo?variant=light"
                 }
                 alt="Logo"
                 className="admin-login-logo"
+                onError={(e) => {
+                  (e.target as HTMLImageElement).src =
+                    theme === "dark"
+                      ? "/images/logo-dark.png"
+                      : "/images/logo-light.png";
+                }}
               />
               <h1 className="admin-login-title">Interní systém</h1>
               <p className="admin-login-subtitle">Přihlaste se ke svému účtu</p>