fix: show local-repo files in the cached-objects UI (#99)

## Why

Local repos store uploaded files in the \`local_files\` table, whereas remote/proxy repos cache into the \`artifacts\` table. The shared **Cached Objects** page always queried the artifacts table via \`/api/v2/remotes/{name}/objects\`, so files uploaded to a local repo (e.g. an internal RPM) were fully stored and servable but showed as **0 objects** in the UI.

## Changes

- Add \`ListLocalArtifacts\`, joining \`local_files\` with \`blobs\` and returning \`models.Artifact\`-shaped rows (size from the blob; access/fetch counters zero and timestamps derived from \`created_at\`, since local files track no access).
- Add \`LocalRoutes\` to the objects handler: \`listLocal\` reads \`local_files\`, \`evictLocal\` deletes via \`DeleteLocalFile\`. Extract shared page/per_page parsing into \`pageBounds\`.
- Mount \`/api/v2/locals/{name}/objects\` (GET + DELETE) in the server.
- Add \`listLocalObjects\`/\`evictLocalObject\` to the UI client and route the Objects page to them when viewing a local repo.
- Cover the listing and eviction paths with a dockerised test.

## Notes

Generated \`repodata/*\` files are not listed — they are produced on the fly from \`rpm_metadata\` and never stored in \`local_files\`, which matches how the repo serves them.

Reviewed-on: #99
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

internal/server/server.go

@@ -121,6 +121,12 @@ func (s *Server) routes() chi.Router {
 			r.Delete("/*", objHandler.Routes().ServeHTTP)
 		})
 
+		r.Route("/locals/{name}/objects", func(r chi.Router) {
+			objHandler := v2.NewObjectsHandler(s.db)
+			r.Get("/", objHandler.LocalRoutes().ServeHTTP)
+			r.Delete("/*", objHandler.LocalRoutes().ServeHTTP)
+		})
+
 		r.Route("/remotes/{name}/files", func(r chi.Router) {
 			r.Put("/*", s.localHandler.Routes().ServeHTTP)
 			r.Get("/*", s.localHandler.Routes().ServeHTTP)