chore(release): 0.39.57

[pitimon]

Summary

• release PR feat: estimate configured auto-router route costs #202 owner-approved weighted auto-router pricing policies
• Claude auto router: Sonnet 60% / Opus 40%
• configured GPT auto routes: Terra 60% / Sol 40%
• all blend values remain routed-estimated and non-exact; fuzzy/missing child pricing fails closed

Verification

• focused release/pricing tests: 26 passed
• npm run ci:local passed
• npm publish --dry-run --json: 174 files
• built bundle embeds 0.39.57, not 0.39.56
• registry confirms 0.39.57 unused

Deploy verification: route token counts stay unchanged; cost becomes weighted estimate and UI marks it estimated/floor.