## Problem
When multiple users create traders with the same exchange + AI model
combination within the same second, they generate identical traderIDs,
causing data conflicts.
Old code (Line 496):
```go
traderID := fmt.Sprintf("%s_%s_%d", req.ExchangeID, req.AIModelID, time.Now().Unix())
```
## Solution
Use UUID to guarantee 100% uniqueness while preserving prefix for debugging:
```go
traderID := fmt.Sprintf("%s_%s_%s", req.ExchangeID, req.AIModelID, uuid.New().String())
```
Example output: `binance_gpt-4_a1b2c3d4-e5f6-7890-abcd-ef1234567890`
## Changes
- `api/server.go:495-497`: Use UUID for traderID generation
- `api/traderid_test.go`: New test file with 3 comprehensive tests
## Tests
✅ All tests passed (0.189s)
✅ TestTraderIDUniqueness - 100 unique IDs generated
✅ TestTraderIDFormat - 3 exchange/model combinations validated
✅ TestTraderIDNoCollision - 1000 iterations without collision
Fixes#893
Co-authored-by: the-dev-z <the-dev-z@users.noreply.github.com>
