Repository broken with "500 Internal Server Error" after git push: "packfile not found" due to missing .idx files

### Gitea Version 1.26.2 ### What happened? ### Description Intermittently, after running a `git push`, a repository becomes completely unreachable and returns a `500 Internal Server Error` on both the web UI and via API calls. Upon inspecting the repository's data directory on the server, we found that new `.pack` files are being created, but their corresponding `.idx` files are completely missing. ### Workaround / Current Solution Manually restoring or regenerating the missing `.idx` files for the orphaned `.pack` files instantly resolves the 500 error, and the repository becomes fully functional again. ### Logs HTTPRequest [I] router: completed GET /api/v1/repos/MyOrganization/MyRepository/branches for 10.x.x.149:61146, 500 Internal Server Error in 58.3ms @ repo/branch.go:284(repo.ListBranches) .../actions/commit_status.go:50:CreateCommitStatusForRunJobs() [E] Failed to create commit status for job 11565: GetCommit[62ee07a1a875bb00af489f68d8cfec64a27ecafb]: packfile not found HTTPRequest [I] router: completed POST /api/actions/runner.v1.RunnerService/UpdateTask for 192.x.x.225:59804, 200 OK in 84.9ms @ <autogenerated>:1(http.Handler.ServeHTTP-fm) HTTPRequest [I] router: completed GET /MyOrganization/MyRepository/src/ for 10.x.x.149:50768, 303 See Other in 52.3ms @ web/web.go:1702(web.registerWebRoutes.func54.(*Router).Group.registerWebRoutes.func54.10.14) services/context/repo.go:919:registerWebRoutes.RepoRefByType.87() [E] GetBranchCommit: packfile not found HTTPRequest [I] router: completed GET /MyOrganization/MyRepository/info/refs?service=git-upload-pack for 10.x.x.169:65235, 401 Unauthorized in 1.6ms @ repo/githttp.go:454(repo.GetInfoRefs) HTTPRequest [I] router: completed GET /MyOrganization/MyRepository/info/refs?service=git-upload-pack for 10.x.x.169:65235, 200 OK in 46.5ms @ repo/githttp.go:454(repo.GetInfoRefs) HTTPRequest [I] router: completed GET /MyOrganization/MyRepository/info/refs?service=git-upload-pack for 10.x.x.230:54028, 401 Unauthorized in 1.9ms @ repo/githttp.go:454(repo.GetInfoRefs) HTTPRequest [I] router: completed POST /MyOrganization/MyRepository/git-upload-pack for 10.x.x.169:65235, 200 OK in 48.1ms @ repo/githttp.go:432(repo.ServiceUploadPack) ### How are you running Gitea? Operating System: Windows Server Deployment Method: Binary (installed directly on Windows Server as a service/executable)