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>

tests/integration/api_user_orgs_test.go

@@ -155,3 +155,44 @@ func TestMyOrgs(t *testing.T) {
 		},
 	}, orgs)
 }
+
+func TestMyOrgsPublicOnly(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	normalUsername := "user2"
+	token := getUserToken(t, normalUsername, auth_model.AccessTokenScopeReadOrganization, auth_model.AccessTokenScopeReadUser, auth_model.AccessTokenScopePublicOnly)
+	req := NewRequest(t, "GET", "/api/v1/user/orgs").
+		AddTokenAuth(token)
+	resp := MakeRequest(t, req, http.StatusOK)
+	var orgs []*api.Organization
+	DecodeJSON(t, resp, &orgs)
+	org3 := unittest.AssertExistsAndLoadBean(t, &user_model.User{Name: "org3"})
+	org17 := unittest.AssertExistsAndLoadBean(t, &user_model.User{Name: "org17"})
+
+	assert.Equal(t, []*api.Organization{
+		{
+			ID:          17,
+			Name:        org17.Name,
+			UserName:    org17.Name,
+			FullName:    org17.FullName,
+			Email:       org17.Email,
+			AvatarURL:   org17.AvatarLink(t.Context()),
+			Description: "",
+			Website:     "",
+			Location:    "",
+			Visibility:  "public",
+		},
+		{
+			ID:          3,
+			Name:        org3.Name,
+			UserName:    org3.Name,
+			FullName:    org3.FullName,
+			Email:       org3.Email,
+			AvatarURL:   org3.AvatarLink(t.Context()),
+			Description: "",
+			Website:     "",
+			Location:    "",
+			Visibility:  "public",
+		},
+	}, orgs)
+}