fix(files): 配置文件改为同目录临时文件 fsync 后原子改名写入，读取返回内容哈希、保存带期望哈希冲突返回 409，磁盘满返回 507，面板提示载入最新或仍然覆盖

panel/src/lib/api.ts

@@ -404,23 +404,25 @@ export const api = {
       `/servers/${name}/files?path=${encodeURIComponent(path)}`,
     ),
 
-  // readServerFile returns one file's bytes (base64). A file over the read
-  // ceiling is a 413, never a silent truncation, because a later save of a
-  // truncated body would destroy the rest of the file.
+  // readServerFile returns one file's bytes (base64) and the sha256 of the file
+  // as stored. A file over the read ceiling is a 413, never a silent truncation,
+  // because a later save of a truncated body would destroy the rest of the file.
   readServerFile: (name: string, path: string) =>
-    request<{ path: string; content: string }>(
+    request<{ path: string; content: string; sha256: string }>(
       "GET",
       `/servers/${name}/file?path=${encodeURIComponent(path)}`,
     ),
 
-  // writeServerFile replaces a file's contents (creating it if absent). Sending
-  // an explicit "" is a deliberate truncate; the wire field is required, but that
-  // is enforced by the caller (this method always sends one).
-  writeServerFile: (name: string, path: string, content: string) =>
-    request<{ path: string; status: string }>(
+  // writeServerFile atomically replaces a file's contents (creating it if
+  // absent). Sending an explicit "" is a deliberate truncate; the wire field is
+  // required, but that is enforced by the caller (this method always sends one).
+  // With expectSha256 (the hash the read returned) a file someone changed since
+  // is refused with 409 file_changed; without it the write is unconditional.
+  writeServerFile: (name: string, path: string, content: string, expectSha256?: string) =>
+    request<{ path: string; status: string; sha256: string }>(
       "PUT",
       `/servers/${name}/file?path=${encodeURIComponent(path)}`,
-      { content },
+      expectSha256 ? { content, expect_sha256: expectSha256 } : { content },
     ),
 
   // Account linking (spec §10). Both are POST: start reports status from the
@@ -756,6 +758,13 @@ export function humanizeError(e: unknown): string {
       return t("maintenance_in_progress");
     case "no_world_volume":
       return t("no_world_volume");
+    // File editor: the file changed after it was opened (another manager saved
+    // it, or the server rewrote it), so the save was refused rather than
+    // overwriting that edit.
+    case "file_changed":
+      return t("file_changed");
+    case "volume_full":
+      return t("volume_full");
     // On-demand backup rationing (data-durability-9): one per server per
     // cooldown, none while the shared backup store is at its cap.
     case "backup_cooldown":