feat: initial BudgetWise budgeting app with Appwrite sync

Full-stack PWA budgeting app installable on Android via Chrome.

Features implemented:
- Monthly balance sheet: income sources (monthly/yearly), buffer (fixed $ or % of income)
- Buckets: regular, savings-goal, and investment types with custom goals
  (amount or % of income, monthly or yearly schedule)
- Debt tracker: manual or auto-EMI (amortization formula), interest rate,
  remaining balance tracking, avalanche-method repayment suggestions
- Loan calculator: max affordable principal and EMI checker based on
  remaining income after all expenses
- Investment projections: compound interest at monthly/yearly rate,
  1/5/10-year projections per bucket
- Deposit / withdraw transactions per bucket with balance history
- Appwrite self-hosted backend: auth, 5 collections (balance_sheets,
  incomes, buckets, debts, transactions)
- scripts/setup-appwrite.cjs: one-command DB setup via node-appwrite
- PWA manifest + service worker (vite-plugin-pwa) for Android install
- Dark mobile-first UI with TailwindCSS, Zustand state, React Router v6

https://claude.ai/code/session_01Ny2EMaZYvzk5SSVDAPgxpP

public/icon.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
+  <rect width="512" height="512" rx="120" fill="#0f172a"/>
+  <rect x="40" y="40" width="432" height="432" rx="90" fill="#1e293b"/>
+  <text x="256" y="340" font-family="system-ui, -apple-system, sans-serif" font-size="240" font-weight="700" text-anchor="middle" fill="#6366f1">B</text>
+  <!-- Dollar sign hint -->
+  <circle cx="340" cy="160" r="48" fill="#22c55e" opacity="0.9"/>
+  <text x="340" y="178" font-family="system-ui" font-size="52" font-weight="700" text-anchor="middle" fill="white">$</text>
+</svg>