feat(sync): add Requesty as automated sync provider

[Thibault00]

Summary

• Adds Requesty as an automated sync provider using the public /v1/models catalog endpoint
• Follows the same pattern as the existing OpenRouter sync provider
• Registers Requesty in the aggregators sync group so it runs on the hourly cron
• Adds REQUESTY_API_KEY to the sync workflow environment (optional, catalog is public)
• Initial sync run: 267 models across all Requesty-supported providers (anthropic, openai, google, xai, deepseek, mistral, vertex, bedrock, azure, etc.)

How it works

The Requesty /v1/models endpoint returns the full public model catalog with pricing, context windows, and capability flags. The sync script:

1. Fetches the public catalog (no auth required for the full list)
2. Filters out region-specific variants (models with @region suffixes)
3. Maps models to canonical provider definitions where possible (using extends)
4. Generates TOML files following the models.dev schema

Test plan

• bun packages/core/script/sync-models.ts requesty --dry-run shows expected changes
• bun packages/core/script/sync-models.ts requesty completes successfully
• bun validate passes with exit code 0
• Second dry run shows no changes (idempotent)

[rekram1-node]

ci fails