Custom Elliptic Curve Parameter Input

## Description:
Create a tool allowing users to input custom elliptic curve parameters and validate them.

## User Story:
As a cryptography researcher, I want to input custom curve parameters and validate them so that I can test my own curve implementations.

Features:
- Input fields for curve parameters (a, b, p, G, n, h)
- Real-time validation of curve parameters
- Check if curve is cryptographically secure
- Calculate curve properties (discriminant, j-invariant)

## Acceptance Criteria:
- [ ] Validate curve equation y² = x³ + ax + b (mod p)
- [ ] Check discriminant ≠ 0
- [ ] Verify generator point is on curve
- [ ] Display warnings for weak curves