Add privacy mode with blur toggle for financial data

- Stimulus controller on global layout (persists across all pages)
- CSS blur effect on .privacy-sensitive elements (8px active, 4px on hover)
- localStorage persistence survives page navigations
- Toggle button on dashboard with aria-pressed for accessibility
- Applied to 28+ views: accounts, budgets, transactions, reports, etc.

Fixes: UTF-8 encoding, global controller mount, aria-pressed attribute

app/assets/tailwind/application.css

@@ -13,6 +13,7 @@
 @import "./google-sign-in.css";
 @import "./date-picker-dark-mode.css";
 @import "./print-report.css";
+@import "./privacy-mode.css";
 
 @layer components {
   .pcr-app{