split per-type registration points into per-type files

- move README per-type sections into docs/<type>/{remote,local,virtual}.md
- split provider.go capability and metadata types into cap_*.go and metadata_*.go
- register providers via internal/provider/all, one file per type
- declare each package type in its own file, registering via init()
- split the e2e caching table and UI type colours/snippets per type

e2e-docker/caching_alpine_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"alpine", "alpine/x86_64/testpkg-1.0-r0.apk", "alpine/x86_64/testpkg-1.0-r0.apk"})
+}

e2e-docker/caching_cargo_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"cargo", "crates/mycrate/mycrate-1.0.0.crate", "crates/mycrate/mycrate-1.0.0.crate"})
+}

e2e-docker/caching_docker_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"docker", "library/testimg/blobs/blobdata", "v2/library/testimg/blobs/blobdata"})
+}

e2e-docker/caching_generic_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"generic", "blobs/hello.bin", "blobs/hello.bin"})
+}

e2e-docker/caching_goproxy_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"goproxy", "goproxy/example.com/mod/@v/v1.0.0.zip", "goproxy/example.com/mod/@v/v1.0.0.zip"})
+}

e2e-docker/caching_helm_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"helm", "charts/mychart-1.0.0.tgz", "charts/mychart-1.0.0.tgz"})
+}

e2e-docker/caching_npm_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"npm", "mypkg/-/mypkg-1.0.0.tgz", "mypkg/-/mypkg-1.0.0.tgz"})
+}

e2e-docker/caching_nuget_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"nuget", "nuget/e2epkg/1.0.0/e2epkg.1.0.0.nupkg", "nuget/e2epkg/1.0.0/e2epkg.1.0.0.nupkg"})
+}

e2e-docker/caching_puppet_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"puppet", "puppet-releases/author-mod-1.0.0.tar.gz", "puppet-releases/author-mod-1.0.0.tar.gz"})
+}

e2e-docker/caching_pypi_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"pypi", "packages/foo-1.0-py3-none-any.whl", "packages/foo-1.0-py3-none-any.whl"})
+}

e2e-docker/caching_rpm_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"rpm", "rpmrepo/Packages/e2e-testpkg-1.0-1.noarch.rpm", "rpmrepo/Packages/e2e-testpkg-1.0-1.noarch.rpm"})
+}

e2e-docker/caching_terraform_test.go

@@ -0,0 +1,7 @@
+//go:build dockere2e
+
+package e2edocker
+
+func init() {
+	cachingCases = append(cachingCases, cachingCase{"terraform", "hashicorp/aws/download/pkg.zip", "v1/providers/hashicorp/aws/download/pkg.zip"})
+}

e2e-docker/caching_test.go

@@ -9,33 +9,23 @@ import (
 	"testing"
 )
 
+type cachingCase struct {
+	pkgType string
+	// path is the request path under /api/v1/remote/<name>/. The provider
+	// derives the upstream URL from it (docker prepends /v2/, terraform
+	// prepends /v1/providers/), and the fixture lives at that resolved path.
+	path    string
+	fixture string
+}
+
+// cachingCases is filled by one caching_<type>_test.go file per package type.
+var cachingCases []cachingCase
+
 // TestCachingPerProvider proxies one immutable artifact for every remote
 // package type through the mock upstream and asserts: first fetch is served
 // from the remote, the second from cache, and the bytes match the origin.
 func TestCachingPerProvider(t *testing.T) {
-	cases := []struct {
-		pkgType string
-		// path is the request path under /api/v1/remote/<name>/. The provider
-		// derives the upstream URL from it (docker prepends /v2/, terraform
-		// prepends /v1/providers/), and the fixture lives at that resolved path.
-		path    string
-		fixture string
-	}{
-		{"generic", "blobs/hello.bin", "blobs/hello.bin"},
-		{"npm", "mypkg/-/mypkg-1.0.0.tgz", "mypkg/-/mypkg-1.0.0.tgz"},
-		{"helm", "charts/mychart-1.0.0.tgz", "charts/mychart-1.0.0.tgz"},
-		{"pypi", "packages/foo-1.0-py3-none-any.whl", "packages/foo-1.0-py3-none-any.whl"},
-		{"rpm", "rpmrepo/Packages/e2e-testpkg-1.0-1.noarch.rpm", "rpmrepo/Packages/e2e-testpkg-1.0-1.noarch.rpm"},
-		{"alpine", "alpine/x86_64/testpkg-1.0-r0.apk", "alpine/x86_64/testpkg-1.0-r0.apk"},
-		{"puppet", "puppet-releases/author-mod-1.0.0.tar.gz", "puppet-releases/author-mod-1.0.0.tar.gz"},
-		{"goproxy", "goproxy/example.com/mod/@v/v1.0.0.zip", "goproxy/example.com/mod/@v/v1.0.0.zip"},
-		{"cargo", "crates/mycrate/mycrate-1.0.0.crate", "crates/mycrate/mycrate-1.0.0.crate"},
-		{"nuget", "nuget/e2epkg/1.0.0/e2epkg.1.0.0.nupkg", "nuget/e2epkg/1.0.0/e2epkg.1.0.0.nupkg"},
-		{"terraform", "hashicorp/aws/download/pkg.zip", "v1/providers/hashicorp/aws/download/pkg.zip"},
-		{"docker", "library/testimg/blobs/blobdata", "v2/library/testimg/blobs/blobdata"},
-	}
-
-	for _, tc := range cases {
+	for _, tc := range cachingCases {
 		t.Run(tc.pkgType, func(t *testing.T) {
 			name := "cache-" + tc.pkgType
 			createRepo(t, fmt.Sprintf(`{