## Why
A balance of exactly **0** could not be saved. Zero is a perfectly valid
balance for any account (an emptied wallet, a paid-off loan, a closed
position), so the app was rejecting legitimate input.
## Root cause
The shared `AmountInput` renders a numeric value of `0` as an **empty
string** (so the field shows the `0.00` placeholder instead of a literal
"0.00"). Several balance forms combined that with the native HTML
`required` attribute — which then rejected the *only* value that renders
empty: `0`. `required` on this input never guarded against a missing
value (the state is always numeric; empty == 0), it only ever blocked
zero.
The backend already accepted `0` (`required|integer`, and Laravel's
`required` treats integer `0` as present), so this was purely a frontend
constraint.
## Changes
- Drop `required` from the balance `AmountInput` in the **Update
balance** dialog and the **Balance history** edit modal.
- Remove the explicit `balanceInCents === 0` guard (and `required`) in
the onboarding **Set balance** step.
- Extend the same fix to the CSV-import **reference balance** field
(identical root cause; the compute path already gates on
`referenceBalance !== null`, so an explicit `0` is a valid anchor).
- Remove the now-orphaned `"Please enter a balance"` translation from
`es.json` / `fr.json`.
- Add feature tests asserting a zero balance can be stored and set as
the current balance.
Transaction and budget amount inputs keep `required` — `0` is not a
meaningful value there, so they are intentionally untouched.
## QA
- **Onboarding balance step**: saving with an empty/zero field now
advances instead of showing "Please enter a balance". ✅
- **Update balance dialog**: set €1,000.00, then overwrote it with €0.00
→ dialog closed and the record persisted. Verified in the DB
(`account_balances.balance = 0`). ✅
- Backend contract locked by new tests in
`AccountBalanceControllerTest`.
## Demo
<!-- PLACEHOLDER: drag the video here -->
_Video to attach: `~/Downloads/allow-zero-balances-demo.mp4`_
## Why
Investment and retirement accounts show balance over time, but there's
no way to see how much money was actually put in versus how much is
current value. Users can't tell at a glance whether their investments
are up or down.
## What
Adds an "invested amount" tracking system across the full stack:
**Backend**
- New `invested_amount` column on `account_balances` (nullable
bigInteger, cents, per-date)
- Auto-sync from providers: Indexa Capital (instruments_cost +
cash_amount), Bitpanda (fiat deposit/withdrawal history), Binance
(90-day windowed deposit/withdrawal with crypto→fiat conversion)
- Manual input support via Update Balance dialog
- Historical invested amount data in all balance evolution APIs (net
worth, account detail)
**Frontend**
- Dashed line on sparkline charts (dashboard + accounts page) showing
per-point historical invested amount alongside balance
- Dashed line on account detail charts (daily AreaChart + monthly
ComposedChart)
- Tooltips with labeled rows: Balance, Invested, Gain/loss (color-coded)
- Invested amount column in balances history modal
- Invested amount field in balance import wizard (CSV mapping)
- Demo account seeder updated with invested amount data
## Screenshots
<img width="1301" height="750" alt="image"
src="https://github.com/user-attachments/assets/0f05ecd0-8b98-47b4-9fa4-027f0311e3bb"
/>
<img width="744" height="374" alt="image"
src="https://github.com/user-attachments/assets/c4daa816-dee0-4f94-957f-317a13bc80d5"
/>
<img width="1267" height="738" alt="image"
src="https://github.com/user-attachments/assets/21df350c-6954-4ff5-8b3c-b858df3a8b3a"
/>
<img width="1301" height="828" alt="image"
src="https://github.com/user-attachments/assets/16f5f021-a926-4e8e-a999-c4ca32d1ea3d"
/>
<img width="1274" height="845" alt="image"
src="https://github.com/user-attachments/assets/62f2dfc0-04f0-4bdb-b072-cf7cd1be77d3"
/>
Víctor Falcón