feat(api): add token introspection and self-deletion endpoint (#37995)

Adds a /api/v1/token endpoint that allows tokens to introspect and
delete themselves.
partially fixes: https://github.com/go-gitea/gitea/issues/33583

Assisted-by: Mistral Vibe:mistral-medium-3.5

---------

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

routers/api/v1/api.go

@@ -88,6 +88,7 @@ import (
 	"gitea.dev/routers/api/v1/packages"
 	"gitea.dev/routers/api/v1/repo"
 	"gitea.dev/routers/api/v1/settings"
+	"gitea.dev/routers/api/v1/token"
 	"gitea.dev/routers/api/v1/user"
 	"gitea.dev/routers/common"
 	"gitea.dev/services/actions"
@@ -976,6 +977,11 @@ func Routes() *web.Router {
 			})
 		})
 
+		// Token introspection and deletion endpoint
+		m.Combo("/token").
+			Get(reqToken(), token.GetCurrentToken).
+			Delete(reqToken(), token.DeleteCurrentToken)
+
 		// Notifications (requires 'notifications' scope)
 		// The notifications API is not available for public-only tokens because a user's notifications mix
 		// public and private repository events in the same mailbox.