chore: 清理 SSR 改造后的历史遗留死代码与误提交产物

- 删除图形验证码整条死链：service/captcha.go、APICaptcha、
  GET /api/captcha、CaptchaService 装配、ErrCaptchaInvalid 及前端
  api.captcha()（注册/登录已改用邮箱验证码，Verify 无任何调用方）
- 删除 GET /api/posts/hot 死路由：APIHotPosts + PostService.HotPosts
  （热门排序走 /api/posts?sort=hot）
- 删除 GET /api/posts/:id/revisions/:revId 死路由：
  APIPostRevisionDetail + PostService.GetRevision + ErrRevisionNotFound
  及前端 api.postRevision()（历史面板仅用列表接口）
- 停止跟踪误提交的 27.5MB Linux 二进制 jiang13-linux-amd64 与
  .vite 依赖缓存；.gitignore 补充对应规则并移除已失效的
  embed_static 条目

router/router.go

@@ -50,7 +50,6 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 	reportSvc := service.NewReportService(filter, settingsSvc, messageSvc, postSvc, commentSvc)
 	backupSvc := service.NewBackupService(cfg.DBPath(), cfg.DataDir)
 	limiter := service.NewRateLimiter(settingsSvc)
-	captchaSvc := service.NewCaptchaService()
 	mailSvc := service.NewMailService(settingsSvc)
 	emailCodeSvc := service.NewEmailCodeService(mailSvc)
 	notifySvc := service.NewNotifyService(messageSvc, mailSvc, settingsSvc)
@@ -82,7 +81,7 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		Post: postSvc, Comment: commentSvc, Message: messageSvc, Notify: notifySvc, Report: reportSvc,
 		Backup: backupSvc, Community: communitySvc, Monitor: monitorSvc,
 		Filter: filter, Limiter: limiter, Settings: settingsSvc,
-		Captcha: captchaSvc, Mail: mailSvc, EmailCode: emailCodeSvc,
+		Mail: mailSvc, EmailCode: emailCodeSvc,
 		OIDC: oidcSvc, Gitea: giteaSvc,
 		Points: service.NewPointsService(), Badge: service.NewBadgeService(),
 		SitePage:        service.NewSitePageService(filter),
@@ -127,13 +126,11 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		pubAPI.GET("/site-branding", h.APISiteBranding)
 		pubAPI.GET("/pages", h.APIPages)
 		pubAPI.GET("/pages/:slug", h.APIPageDetail)
-		pubAPI.GET("/captcha", h.APICaptcha)
 		pubAPI.GET("/register/config", h.APIRegisterConfig)
 		pubAPI.POST("/register/email-code", middleware.RateLimitMiddleware(limiter, "register"), h.APISendRegisterEmailCode)
 		pubAPI.POST("/password-reset/email-code", middleware.RateLimitMiddleware(limiter, "register"), h.APISendResetEmailCode)
 		pubAPI.POST("/password-reset", middleware.RateLimitMiddleware(limiter, "login"), h.APIResetPassword)
 		pubAPI.GET("/posts", h.APIPosts)
-		pubAPI.GET("/posts/hot", h.APIHotPosts)
 		pubAPI.GET("/tags", h.APITags)
 		pubAPI.GET("/comments/recent", h.APIRecentComments)
 		// search / recent 须在 :id 之前
@@ -164,7 +161,6 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		api.PUT("/posts/:id", h.APIUpdatePost)
 		api.DELETE("/posts/:id", h.APIDeletePost)
 		api.GET("/posts/:id/revisions", h.APIPostRevisions)
-		api.GET("/posts/:id/revisions/:revId", h.APIPostRevisionDetail)
 		api.POST("/posts/:id/like", h.APIToggleLike)
 		api.POST("/posts/:id/favorite", h.APIToggleFavorite)
 		api.POST("/posts/:id/resolve", h.APISetQuestionResolved)