Add accounts expansion, analytics, exchange rates, API tokens, PWA support, and UI overhaul

- Expand Account model with account_type (pension, savings, liability, crypto), new banks/currencies (BTC, XMR, FCL, ROP, VOL, MEMP, MPAT, MORTGAGE), and next_payment field
- Add exchange rate endpoint (BCCR integration), analytics endpoint, paste-import for transactions, and API token management
- Add PWA manifest, service worker, and app icons
- Redesign dashboard, transactions, transfers, and login pages with theme support
- Add billing cycle selector, confirm dialog, and paste import modal components
- One-time DB reset in deploy workflow for schema migration

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

backend/app/config.py

@@ -7,6 +7,8 @@ class Settings(BaseSettings):
     ACCESS_TOKEN_EXPIRE_MINUTES: int = 60 * 24 * 30  # 30 days
     ADMIN_USERNAME: str = "admin"
     ADMIN_PASSWORD: str = "admin"
+    BCCR_API_EMAIL: str = ""
+    BCCR_API_TOKEN: str = ""
 
     class Config:
         env_file = ".env"