docs: add README, per-resource examples, unit tests, CI, and pre-commit

- Add README.md with provider docs, resource/data-source reference, and
  development instructions
- Reorganize examples into per-resource-type subdirectories following
  Terraform provider conventions, add missing pypi/npm/puppet examples
- Add unit tests for helpers, HTTP client, model conversions, and
  provider registration
- Add Woodpecker CI pipelines for lint, test, and build
- Add pre-commit config with standard and Go-specific hooks

examples/resources/artifactapi_remote_docker/main.tf

@@ -0,0 +1,32 @@
+terraform {
+  required_providers {
+    artifactapi = {
+      source  = "git.unkin.net/unkin/artifactapi"
+      version = "0.0.1"
+    }
+  }
+}
+
+provider "artifactapi" {
+  endpoint = "https://artifactapi.example.com"
+}
+
+# Docker remote proxies a container registry.
+# The provider auto-classifies: tag manifests are mutable, blobs are immutable.
+resource "artifactapi_remote_docker" "dockerhub" {
+  name        = "dockerhub"
+  base_url    = "https://registry-1.docker.io"
+  description = "Docker Hub registry"
+
+  immutable_ttl    = 0
+  mutable_ttl      = 300
+  ban_tags_enabled = true
+  ban_tags         = ["latest"]
+
+  patterns = [
+    "^library/almalinux",
+    "^library/postgres",
+    "^library/redis",
+    "^bitnami/",
+  ]
+}