fix: Unify public-only token filtering in API queries and repo access checks (#37118) (#37773)

backport #37118 

This PR closes remaining `public-only` token gaps in the API by making
the restriction apply consistently across repository, organization,
activity, notification, and authenticated `/api/v1/user/...` routes.

Previously, `public-only` tokens were still able to:
- receive private results from some list/search/self endpoints,
- access repository data through ID-based lookups,
- and reach several authenticated self routes that should remain
unavailable for public-only access.

This change treats `public-only` as a cross-cutting visibility boundary:
- list/search endpoints now filter private resources consistently,
- repository lookups enforce the same restriction even when addressed
indirectly,
- and self routes that inherently expose or mutate private account state
now reject `public-only` tokens.

---
Generated by a coding agent with Codex 5.2

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>
Co-authored-by: Nicolas <bircni@icloud.com>

routers/api/v1/user/repo.go

@@ -19,12 +19,15 @@ import (
 func listUserRepos(ctx *context.APIContext, u *user_model.User, private bool) {
 	opts := utils.GetListOptions(ctx)
 
-	repos, count, err := repo_model.GetUserRepositories(ctx, repo_model.SearchRepoOptions{
+	searchOpts := repo_model.SearchRepoOptions{
 		Actor:       u,
 		Private:     private,
 		ListOptions: opts,
 		OrderBy:     "id ASC",
-	})
+	}
+	searchOpts.ApplyPublicOnly(ctx.PublicOnly)
+
+	repos, count, err := repo_model.GetUserRepositories(ctx, searchOpts)
 	if err != nil {
 		ctx.APIErrorInternal(err)
 		return
@@ -79,8 +82,7 @@ func ListUserRepos(ctx *context.APIContext) {
 	//   "404":
 	//     "$ref": "#/responses/notFound"
 
-	private := ctx.IsSigned
-	listUserRepos(ctx, ctx.ContextUser, private)
+	listUserRepos(ctx, ctx.ContextUser, ctx.IsSigned)
 }
 
 // ListMyRepos - list the repositories you own or have access to.
@@ -110,6 +112,7 @@ func ListMyRepos(ctx *context.APIContext) {
 		Private:            ctx.IsSigned,
 		IncludeDescription: true,
 	}
+	opts.ApplyPublicOnly(ctx.PublicOnly)
 
 	repos, count, err := repo_model.SearchRepository(ctx, opts)
 	if err != nil {