Vendor Effect AI provider forks

[K-Mistele]

Summary

• Vendor and publish HumanLayer-owned OpenAI, Anthropic, and OpenAI-compatible Effect AI providers from the immutable 4.0.0-rc.112 upstream artifacts.
• Preserve the tool-result encoding and stream-error fixes in normal source, give forked Effect services distinct @humanlayer/effect-ai-* context keys, and document provenance/local deltas.
• Migrate Fold consumers to normal workspace dependencies on the forks and remove the two Bun patch files and patch metadata.
• Extend release build/staging/validation for wildcard provider exports, Node ESM/declarations, provenance files, and staged consumer dependency pinning.
• Add clean npm and pnpm packed-artifact consumers that import Fold plus every provider and exercise the OpenAI and Anthropic tool-result encoders.
• Document the one-time bootstrap publish and npm CLI trusted-publishing setup.

Release sequencing

The three bootstrap provider packages (0.1.21-provider-bootstrap.0) and their trusted publishers have already been created. After this PR merges, publish v0.1.21; the GitHub OIDC release workflow will publish the stable provider packages at 0.1.21 and move their latest tags.

Synclayer must be migrated in a follow-up after that release, because its current published Fold 0.1.20 dependencies still import the upstream providers.

Validation

• bun install --frozen-lockfile
• bun run typecheck
• bun run lint
• bun run format:check
• bun run test
• bun run build:packages --version 0.1.21
• bun run release:prepare --version 0.1.21
• bun run release:validate --version 0.1.21 (includes clean npm + pnpm consumers)
• bun run release:publish --version 0.1.21 --tag ci --dry-run