enhance(ui): use OpenAPI 3.0 spec in API viewer, add spec buttons (#38478)

Follow-ups from https://github.com/go-gitea/gitea/pull/37038:

- Render the OpenAPI 3.0 spec in the API viewer, it is richer than the
Swagger 2.0 rendering
- Replace the back link with gitea-styled buttons to view both specs and
return to Gitea, flowing above swagger-ui on viewports where they would
overlap the title
- Key `VisibilityModes` by the string enum type, now named
`VisibilityString`, removing the `string()` casts at API call sites
- Drop the raw visibility strings from the `Service` settings struct in
favor of the typed mode fields, which also removes the org default
visibility row from the admin config page
- Fix two pre-existing issues surfaced in review: an invalid
`DEFAULT_USER_VISIBILITY` was silently accepted as public, and the org
visibility error message showed the enum zero value instead of the
submitted input

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/structs/admin_user.go

@@ -29,7 +29,7 @@ type CreateUserOption struct {
 	// Whether the user has restricted access privileges
 	Restricted *bool `json:"restricted"`
 	// User visibility level: public, limited, or private
-	Visibility UserVisibility `json:"visibility" binding:"In(,public,limited,private)"`
+	Visibility VisibilityString `json:"visibility" binding:"In(,public,limited,private)"`
 
 	// For explicitly setting the user creation timestamp. Useful when users are
 	// migrated from other systems. When omitted, the user's creation timestamp
@@ -78,5 +78,5 @@ type EditUserOption struct {
 	// Whether the user has restricted access privileges
 	Restricted *bool `json:"restricted"`
 	// User visibility level: public, limited, or private
-	Visibility UserVisibility `json:"visibility" binding:"In(,public,limited,private)"`
+	Visibility VisibilityString `json:"visibility" binding:"In(,public,limited,private)"`
 }

modules/structs/org.go

@@ -22,7 +22,7 @@ type Organization struct {
 	// The location of the organization
 	Location string `json:"location"`
 	// The visibility level of the organization (public, limited, private)
-	Visibility UserVisibility `json:"visibility"`
+	Visibility VisibilityString `json:"visibility"`
 	// Whether repository administrators can change team access
 	RepoAdminChangeTeamAccess bool `json:"repo_admin_change_team_access"`
 	// username of the organization
@@ -60,7 +60,7 @@ type CreateOrgOption struct {
 	// The location of the organization
 	Location string `json:"location" binding:"MaxSize(50)"`
 	// possible values are `public` (default), `limited` or `private`
-	Visibility UserVisibility `json:"visibility" binding:"In(,public,limited,private)"`
+	Visibility VisibilityString `json:"visibility" binding:"In(,public,limited,private)"`
 	// Whether repository administrators can change team access
 	RepoAdminChangeTeamAccess bool `json:"repo_admin_change_team_access"`
 }
@@ -78,7 +78,7 @@ type EditOrgOption struct {
 	// The location of the organization
 	Location *string `json:"location" binding:"MaxSize(50)"`
 	// possible values are `public`, `limited` or `private`
-	Visibility *UserVisibility `json:"visibility" binding:"In(,public,limited,private)"`
+	Visibility *VisibilityString `json:"visibility" binding:"In(,public,limited,private)"`
 	// Whether repository administrators can change team access
 	RepoAdminChangeTeamAccess *bool `json:"repo_admin_change_team_access"`
 }

modules/structs/user.go

@@ -51,7 +51,7 @@ type User struct {
 	// the user's description
 	Description string `json:"description"`
 	// User visibility level option: public, limited, private
-	Visibility UserVisibility `json:"visibility"`
+	Visibility VisibilityString `json:"visibility"`
 
 	// user counts
 	Followers    int `json:"followers_count"`

modules/structs/visible_type.go

@@ -18,10 +18,10 @@ const (
 )
 
 // VisibilityModes is a map of Visibility types
-var VisibilityModes = map[string]VisibleType{
-	"public":  VisibleTypePublic,
-	"limited": VisibleTypeLimited,
-	"private": VisibleTypePrivate,
+var VisibilityModes = map[VisibilityString]VisibleType{
+	VisibilityStringPublic:  VisibleTypePublic,
+	VisibilityStringLimited: VisibleTypeLimited,
+	VisibilityStringPrivate: VisibleTypePrivate,
 }
 
 // IsPublic returns true if VisibleType is public
@@ -43,27 +43,27 @@ func (vt VisibleType) IsPrivate() bool {
 func (vt VisibleType) String() string {
 	for k, v := range VisibilityModes {
 		if vt == v {
-			return k
+			return string(k)
 		}
 	}
 	return ""
 }
 
-// ExtractKeysFromMapString provides a slice of keys from map
-func ExtractKeysFromMapString(in map[string]VisibleType) (keys []string) {
-	for k := range in {
-		keys = append(keys, k)
+// VisibilityModeKeys returns the visibility mode names (public, limited, private)
+func VisibilityModeKeys() (keys []string) {
+	for k := range VisibilityModes {
+		keys = append(keys, string(k))
 	}
 	return keys
 }
 
-// UserVisibility defines the visibility level of a user or organization as
-// rendered in API payloads. The DB representation is VisibleType (int).
-// swagger:enum UserVisibility
-type UserVisibility string
+// VisibilityString defines the visibility level of a user/organization/team as
+// rendered in API and config payloads. The DB representation is VisibleType (int).
+// swagger:enum VisibilityString
+type VisibilityString string
 
 const (
-	UserVisibilityPublic  UserVisibility = "public"
-	UserVisibilityLimited UserVisibility = "limited"
-	UserVisibilityPrivate UserVisibility = "private"
+	VisibilityStringPublic  VisibilityString = "public"
+	VisibilityStringLimited VisibilityString = "limited"
+	VisibilityStringPrivate VisibilityString = "private"
 )