[Price] deepseek-v4-pro cost doesn't match DeepSeek's official pricing page

The current cost for deepseek-v4-pro in the deepseek provider is:

• input: 0.435
• output: 0.87
• cache_read: 0.003625

DeepSeek's official pricing page (中文, verified 2026-09-19) lists for deepseek-v4-pro (DeepSeek-V4-Pro-0813), off-peak rates in CNY / 1M tokens (peak is exactly 2×):

At the prevailing CNY/USD rate (~6.71 on 2026-09-19) that is roughly /bin/zsh.67 input / .01 output / /bin/zsh.022 cache_read — none of the current figures match, and the internal ratios (0.435 : 0.87 : 0.003625) don't match the official 4.5 : 13.5 : 0.15 either, so this does not look like a single exchange-rate conversion of any published tier.

For comparison, deepseek-v4-flash / deepseek-flash on the same provider (0.15 / 0.6 / 0.003) does match the official off-peak rates (¥1 / ¥4 / ¥0.02 at the same rate), so the v4-pro entry looks stale or mis-converted.

Related: #5218 (schema can't express the peak/off-peak split), #6672.

Happy to send a PR if the intended convention is "off-peak CNY ÷ current rate" (≈ 0.67 / 2.01 / 0.022).

Start at the deepseek provider entry for the deepseek-v4-pro model and compare its pricing fields with the deepseek-v4-flash and deepseek-flash entries. Check the official pricing linked in the issue and the related schema discussion in #5218 before choosing the intended peak/off-peak convention; done means the stored values match that convention and the comparison entries remain consistent.