Enhance take-profit and stop-loss inputs

[JeremyZeng77]

Fixes #17

Summary

• Add TP/SL price move shortcut buttons using 1%, 2%, and 5% favorable/adverse price moves for long and short orders.
• Keep TP/SL price and percentage fields in sync when a shortcut is selected.
• Show estimated profit/loss amount in the selected collateral asset alongside the existing P/L percentage.

Verification

• git diff --check
• npm run build (passes; existing Svelte/a11y/dependency warnings remain)

Bounty / payout

Requesting assignment and consideration for the crypto bounty on #17.

Preferred payout: USDT TRC20 TWupTAoFjxR2VmqUUvzhfmUwXVZR6Kvz1Y
Backup payout: PayPal https://paypal.me/Jeremytsangchina

[JeremyZeng77]

Verification note: the Vercel status failure reports "Account is blocked." Local validation for this branch passed with git diff --check and npm run build; the build completed with existing Svelte/a11y/dependency warnings.