Document Terraform HTTP backend compatibility requirements

[nathanhruby]

Question

What exact Terraform HTTP backend request, response, status, query-parameter, retry, lock, unlock, force-unlock, and deletion behaviors must the PocketBase implementation preserve, and which current United behaviors are accidental rather than protocol requirements?

[nathanhruby]

Resolved by Terraform HTTP backend compatibility research on branch research/terraform-http-contract, commit aa7f338.

Gist: preserve the documented Terraform and OpenTofu HTTP state and locking contract, including GET/POST/DELETE state operations, optional LOCK/UNLOCK, JSON lock payloads, Content-MD5 handling, uppercase ID lock propagation, supported success and conflict statuses, retry behavior, authentication and TLS expectations, and serialized single-writer concurrency. Existing S3 migration remains out of scope. The artifact separates protocol requirements from current United behavior and records compatibility tests and newly surfaced decisions.