fix: prevent crash when clicking Ignore/Report without login

Added login checks for all user actions in FeedDetail:
- Star/Unstar topic
- Thanks author
- Ignore topic
- Report topic
- Reply to topic

These actions now:
1. Check if user is logged in before executing
2. Show login prompt if not authenticated
3. Properly handle nil values with guard statements
4. Show error messages if required data is missing

This fixes the crash reported in issue #4 when non-logged-in users
click Ignore or Report buttons.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: graycreate

V2er/State/DataFlow/Actions/FeedDetailActions.swift

@@ -59,15 +59,25 @@ struct FeedDetailActions {
         var id: String
 
         func execute(in store: Store) async {
+            // Check if user is logged in
+            guard AccountState.hasSignIn() else {
+                Toast.show("请先登录")
+                dispatch(LoginActions.ShowLoginPageAction(reason: "需要登录才能收藏主题"))
+                return
+            }
+
             let state = store.appState.feedDetailStates[id]
             let hadStared = state?.model.headerInfo?.hadStared ?? false
             Toast.show(hadStared ? "取消收藏" : "收藏中")
-            let once = state?.model.once
+            guard let once = state?.model.once else {
+                Toast.show("操作失败，请刷新页面")
+                return
+            }
             let headers: Params = Headers.topicReferer(id)
 
             let result: APIResult<FeedDetailInfo> = await APIService.shared
                 .htmlGet(endpoint: hadStared ? .unStarTopic(id: id): .starTopic(id: id),
-                         ["once": once!],
+                         ["once": once],
                          requestHeaders: headers)
             dispatch(StarTopicDone(id: id, hadStared: hadStared, result: result))
         }
@@ -86,12 +96,22 @@ struct FeedDetailActions {
         var id: String
 
         func execute(in store: Store) async {
+            // Check if user is logged in
+            guard AccountState.hasSignIn() else {
+                Toast.show("请先登录")
+                dispatch(LoginActions.ShowLoginPageAction(reason: "需要登录才能感谢作者"))
+                return
+            }
+
             Toast.show("发送中")
             let state = store.appState.feedDetailStates[id]
-            let once = state?.model.once
+            guard let once = state?.model.once else {
+                Toast.show("操作失败，请刷新页面")
+                return
+            }
 
             let step1Result: APIResult<SimpleModel>  = await APIService.shared
-                .post(endpoint: .thanksAuthor(id: id), ["once": once!])
+                .post(endpoint: .thanksAuthor(id: id), ["once": once])
 
             var success: Bool = false
             var toast = "感谢发送失败"
@@ -116,11 +136,21 @@ struct FeedDetailActions {
         var id: String
 
         func execute(in store: Store) async {
+            // Check if user is logged in
+            guard AccountState.hasSignIn() else {
+                Toast.show("请先登录")
+                dispatch(LoginActions.ShowLoginPageAction(reason: "需要登录才能忽略主题"))
+                return
+            }
+
             Toast.show("忽略中")
             let state = store.appState.feedDetailStates[id]
-            let once = state?.model.once
+            guard let once = state?.model.once else {
+                Toast.show("操作失败，请刷新页面")
+                return
+            }
             let result: APIResult<FeedInfo> = await APIService.shared
-                .htmlGet(endpoint: .ignoreTopic(id: id), ["once": once!])
+                .htmlGet(endpoint: .ignoreTopic(id: id), ["once": once])
             var ignored = false
             if case let .success(result) = result {
                 ignored = result?.isValid() ?? false
@@ -141,11 +171,22 @@ struct FeedDetailActions {
         var id: String
 
         func execute(in store: Store) async {
+            // Check if user is logged in
+            guard AccountState.hasSignIn() else {
+                Toast.show("请先登录")
+                dispatch(LoginActions.ShowLoginPageAction(reason: "需要登录才能举报主题"))
+                return
+            }
+
             Toast.show("举报中")
-            let state = store.appState.feedDetailStates[id]!
+            guard let state = store.appState.feedDetailStates[id],
+                  let reportLink = state.model.reportLink else {
+                Toast.show("操作失败，请刷新页面")
+                return
+            }
 
             let result: APIResult<DailyInfo> = await APIService.shared
-                .htmlGet(endpoint: .general(url: state.model.reportLink!),
+                .htmlGet(endpoint: .general(url: reportLink),
                          requestHeaders: Headers.TINY_REFERER)
             var reported = false
             if case let .success(result) = result {
@@ -166,10 +207,26 @@ struct FeedDetailActions {
         var id: String
 
         func execute(in store: Store) async {
+            // Check if user is logged in
+            guard AccountState.hasSignIn() else {
+                Toast.show("请先登录")
+                dispatch(LoginActions.ShowLoginPageAction(reason: "需要登录才能回复主题"))
+                return
+            }
+
             Toast.show("回复中")
-            let state = store.appState.feedDetailStates[id]!
+            guard let state = store.appState.feedDetailStates[id] else {
+                Toast.show("操作失败，请刷新页面")
+                return
+            }
+
+            guard let once = state.model.once else {
+                Toast.show("操作失败，请刷新页面")
+                return
+            }
+
             var params: Params = Params()
-            params["once"] = state.model.once
+            params["once"] = once
             params["content"] = state.replyContent
 
             let result: APIResult<FeedDetailInfo> = await APIService.shared