feat: add local repository type with repo_type field (#49)

Introduces repo_type (remote/local) as a separate axis from package_type
so that any package type can be hosted locally. A terraform local repo
is package_type=terraform + repo_type=local.

- Remote model gains RepoType field (defaults to "remote")
- Database schema adds repo_type column with migration for existing DBs
- V1 proxy adds /api/v1/local/{name}/* route for serving local files
- V2 upload via PUT /api/v2/remotes/{name}/files/{ns}/{type}/{file}.zip
  validates filename matches terraform-provider-{type}_{ver}_{os}_{arch}.zip
  and returns 409 on duplicate (no overwrites)
- index.json and {version}.json are computed on-the-fly from uploaded zips
  rather than stored as separate files
- V2 create validates repo_type and requires base_url only for remotes

---------

Co-authored-by: Ben Vincent <ben@unkin.net>
Reviewed-on: #49

internal/server/server.go

@@ -91,7 +91,9 @@ func (s *Server) routes() chi.Router {
 	r.Get("/health", s.handleHealth)
 	r.Get("/", s.handleRoot)
 
-	proxyHandler := v1.NewProxyHandler(s.engine, s.virtEngine, s.db)
+	localHandler := v2.NewLocalHandler(s.db, s.store)
+
+	proxyHandler := v1.NewProxyHandler(s.engine, s.virtEngine, s.db, s.store, localHandler)
 	r.Mount("/api/v1", proxyHandler.Routes())
 
 	remotesHandler := v2.NewRemotesHandler(s.db)
@@ -114,6 +116,12 @@ func (s *Server) routes() chi.Router {
 			r.Get("/", objHandler.Routes().ServeHTTP)
 			r.Delete("/*", objHandler.Routes().ServeHTTP)
 		})
+
+		r.Route("/remotes/{name}/files", func(r chi.Router) {
+			r.Put("/*", localHandler.Routes().ServeHTTP)
+			r.Get("/*", localHandler.Routes().ServeHTTP)
+			r.Delete("/*", localHandler.Routes().ServeHTTP)
+		})
 	})
 
 	return r