#194 developer: use server passage budget from search#843

Summary

• keep passage sizing as server-side policy, with no client knob
• stop sending passage_budget on developer-search requests
• trust server-shaped passage text without a local cut when passage_budget_applied is present
• retain the 1,200-character fallback when that field is absent, covering old servers and rollout-off responses

Decision: server-side policy, no client knob.

The fallback retains the TODO to remove it after firecrawl/search#843 is enabled everywhere.

Verification

• pnpm run format:check
• pnpm run type-check
• pnpm run build
• pnpm run test (423 passed)