feat(compiler): compose check and bundle pipeline

[ofabiodev]

Summary

Adds the compiler orchestrator, providing high-level APIs for checking Puff projects and generating Minecraft datapacks.

Changes

• Add compiler.Check and compiler.Bundle pipelines.
• Support project discovery, target/output overrides, diagnostics, cancellation, and deterministic datapack publication.
• Add integration tests for valid and invalid projects, filesystem safety, output preservation, and repeated builds.

Testing

cd src
go test ./...
go vet ./...