fix: cors sse, body limit, model prices, cheapest gap, limit trace, score precision

[carlosatta]

Changes

• CORS on hijacked SSE streams (openai.ts, anthropic.ts): after reply.hijack(), manually set CORS headers on reply.raw — @fastify/cors is bypassed after hijack, causing silent browser failures on streaming responses

• Body limit 256MB (server.ts): Fastify default is 1MB; raised to 256MB to support vision uploads and large context requests

• Model price fallback on edit (ModelFormPage.tsx): editModel() now substitutes preset prices when stored inputPerMillion/outputPerMillion are 0, preventing models from being treated as free by the cheapest policy

• Cheapest policy gap (cheapest.ts): paidCeiling changed from 0.999 to 0.5 when free models exist — ensures a meaningful visual and scoring gap between free ## Changes

• CORS on hijacked SSE streams (openai.ts, anthropic.ts): after reply.hijack(), manually set CORS headers on reply.raw — @fastify/cors is bypassed after hijack, causing silent browser failures on streaming responses

• **Bo)

• **CORS di- Body limit 256MB (server.ts): Fastify default is 1MB; raised to 256MB to support vision uploads and large context requests

• Model price fallback on edit (ModelFormPage.tsx): editModel() now substitutes preset pric e- Model price fallback on edit (ModelFormPage.tsx): editModel() now substitutes preset prices when stored inputPerMillio c- **Cheapest policy gation to reflect new 0.5` ceiling