Fix notifications --mine outside git repositories (#1056)

Fixes #1055.

## Root cause
`tea notifications --mine` still initialized full repository context before checking the global notification scope, so it probed the current working directory with git and could select or fail on repository-derived context even though repository data is not needed.

## Changes
- Add an InitCommand option to skip local git repository discovery when a command does not need repository context.
- Use that option for notification list and mark-as operations when `--mine` is set.
- Add a regression test that makes `git` fail if invoked and verifies `notifications --mine` still uses the global notifications API.

## Tests
- `go test ./cmd/notifications ./modules/context`

Reviewed-on: https://gitea.com/gitea/tea/pulls/1056

cmd/notifications/list.go

@@ -63,12 +63,12 @@ func listNotifications(requestCtx stdctx.Context, cmd *cli.Command, status []git
 	var news []*gitea.NotificationThread
 	var err error
 
-	ctx, err := context.InitCommand(cmd)
+	all := cmd.Bool("mine")
+	ctx, err := context.InitCommandWithOptions(cmd, context.InitOptions{SkipLocalRepo: all})
 	if err != nil {
 		return err
 	}
 	client := ctx.Login.Client()
-	all := ctx.Bool("mine")
 
 	// This enforces pagination (see https://github.com/go-gitea/gitea/issues/16733)
 	listOpts := flags.GetListOptions(cmd)