Extract node library to dedicated package

[bchapuis]

Summary

Extract the node library into a standalone package (@dafthunk/nodes) to enable tree-shaking, code splitting, and clearer boundaries between node definitions and platform-specific execution.

Key components to move

• apps/api/src/nodes/base-node-registry.ts - Registry pattern
• apps/api/src/nodes/types.ts - ExecutableNode base class and parameter types
• All category folders (anthropic/, text/, image/, etc.)
• apps/api/src/nodes/parameter-mapper.ts - API ↔ node format conversion

Decoupling required

• Abstract NodeContext to remove direct Cloudflare bindings (env.DB, env.AI, env.RESSOURCES)
• Convert cloudflare-node-registry.ts to dynamic/lazy loading
• Create NodeEnvironment interface for storage, secrets, and AI providers
• Separate nodes by tier: core (no deps) → integration (API deps) → AI (provider deps)

Dependencies

• @dafthunk/types (already shared)
• ~50+ npm packages for specific integrations