[BACKEND] Add a deposit / "add funds" endpoint (mock funding)

[Trovic1]

Summary

Today a new user signs up with a 0 balance and there is no way to add funds — the only money movement is a transfer between existing users (src/routes/WalletRoutes.js). Add a deposit endpoint that credits the authenticated user's wallet, plus a small "Add funds" UI, so a fresh account can actually start using the app. This is mock funding (no real payment processor) — it simulates a top-up for demo purposes and must be clearly labeled as such.

Scope

• backend + frontend

Likely files

• src/routes/WalletRoutes.js (new POST /wallet/deposit)
• src/services/WalletService.js (a deposit function, reusing the atomic update + transaction-record flow)
• src/models/Transaction.js (record the deposit as an incoming entry)
• src/middleware/ (amount validation, reuse ValidateTransfer's rules)
• frontend/src/pages/Dashboard.jsx (an "Add funds" button on the hero tile)
• frontend/src/services/api.js (a deposit call)
• optionally frontend/src/components/ui.jsx (reuse the modal/confirm surface)

Acceptance criteria

• Authenticated POST /wallet/deposit credits the caller's wallet by a validated amount
• Amount is validated server-side: positive, numeric, rounded to 2 decimals, with a sane upper cap
• A transaction record is created so the deposit shows in the transactions list
• Works in both Postgres and local-JSON storage modes
• Frontend exposes an "Add funds" action that updates the balance counter on success
• UI clearly labels this as demo / mock funding (no real money)
• Identity comes from the JWT, never from the request body

Verification

• Sign up a fresh account ($0), add funds, and confirm the balance and transactions list update
• Send a non-positive / NaN / oversized amount and confirm a 4xx with a clear message
• Confirm the deposit appears as an incoming transaction in both storage modes

Labels: backend, frontend, enhancement, help wanted

---

[arishaix]

can you assign it to me??