feat: add native TypeSafe Jev System One support

[aofee]

Summary

• add TypeSafe as a first-class API-key platform with native POST /v1/systemone support for jev-latest
• validate and pass through System One noul, choice, and score requests, with model discovery and Composite routing
• record native token usage with an input-only $0.042/MTok fallback price and channel pricing overrides
• use the existing account scheduling, concurrency, cooldown, failover, billing, quota, audit, and usage-recording paths
• expose TypeSafe / Jev in the account, group, channel pricing, quota, filter, and usage interfaces, with English and Chinese documentation

Protocol boundary

This is separate from #7387, which uses TypeSafe only as an internal content-moderation engine. This PR makes Jev available to gateway users through its native System One contract. It does not make Jev compatible with Chat Completions, Responses, Anthropic Messages, or streaming clients.

Error and billing behavior

• 400 and 422 are returned without retrying another account
• 401 is treated as an account credential failure
• 429, 529, network failures, timeouts, and 5xx use the existing cooldown/error-policy and account-failover paths
• request bodies, upstream error bodies, and credentials are not logged
• default pricing is $0.042/MTok input and $0 output; channel pricing can override both

Testing

• backend unit and integration suites
• System One validation, mock-upstream forwarding, usage, pricing, error-policy, cooldown, and failover tests
• existing TypeSafe content-moderation regression tests
• golangci-lint v2
• frontend ESLint, TypeScript checks, affected Vitest suites, and production build

No real TypeSafe API was called.

Closes #7299

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