Fix surplus math for players projected below $3M

[cschmertz]

Right now any projection under $3.0M comes back as the string "Minimum Salary", and every spot that computes surplus turns that into $0. That makes fairly paid minimum players look like bad contracts. Russell Westbrook, paid the $2.3M vet minimum, shows -2.3M surplus. A player projected at $2.9M on a $2.3M deal shows -2.3M too, when he's really a small bargain. The same thing happens in every row of the multi-year table, so Total Contract Surplus gets dragged down for basically every cheap veteran on the list.

The fix: calculateSalary now always returns a number, floored at a new MIN_SALARY constant (2.3, the approximate vet minimum cap hit in 2025-26 dollars, which matches what most of the min guys in players.js are actually paid). The "Min" label still shows for anything under $3M, it just happens at display time instead of inside the math. In the future years table the floored value gets inflated by the same scalers as everything else, so a min player on a future min deal nets out to roughly zero surplus like you'd expect.

I also switched the surplus color check from "greater than 0" to "0 or more", since exactly-zero surpluses are common now and a fair min contract shouldn't render red.

Before and after with the default sliders (70 games, 30 minutes):

• Westbrook: was -2.3M surplus, now 0.0M
• Jokic: $68.2M projected value and +13.0M surplus, identical to before

Nothing changes for any player whose projection is above $3M. Tested in the browser.