fix(official-sync): 发布成功后立即提交版本状态事务

publish() 切换 current symlink 后，写最终 snapshot 或 complete_version_state
若失败会经 ? 提前返回，此时 VersionStateGuard 尚未 commit，其 Drop 会把这个
磁盘上已发布（current 已指向）的版本记入 failed_versions，造成状态与磁盘不一致。

改为在 publish() 成功后立即取出完成记录并 commit 版本状态事务，随后 snapshot
与 version-state 写入失败降级为可下轮重试的警告（不再 ? 中断、不再误记 failed）；
snapshot_written 也改为仅在实际写入成功时置 Some。

对应 issue #18 维护清单 1-3。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

infrastructure/src/official_update.rs

@@ -1389,10 +1389,27 @@ impl OfficialUpdateService {
         let published_version_path = publish_layout
             .publish(&publish_plan)
             .map_err(anyhow::Error::msg)?;
+        // current symlink 已切换，资源发布成功。先取出完成版本记录并立即结束版本状态
+        // 事务，使后续 snapshot / version-state 写入失败不会把这个已发布版本经
+        // VersionStateGuard::Drop 误记为 failed，而是降级为可下轮重试的警告。
+        let completed_record = version_state_guard.record()?.clone();
+        version_state_guard.commit();
+
         let final_snapshot_path = snapshot_path_for(config, &published_version_path);
-        if config.snapshot_path.is_some() {
-            write_snapshot(&final_snapshot_path, &current_update_snapshot)?;
+        let snapshot_written = if config.snapshot_path.is_some() {
+            match write_snapshot(&final_snapshot_path, &current_update_snapshot) {
+                Ok(()) => true,
+                Err(error) => {
+                    progress(OfficialUpdateProgress::new(
+                        "publish",
+                        format!("资源已发布，但写入最终 snapshot 失败（下轮可重试）：{error}"),
+                    ));
+                    false
                 }
+            }
+        } else {
+            false
+        };
 
         report.update_status = OfficialUpdateStatus::Downloaded;
         report.active_resource_root = published_version_path.clone();
@@ -1409,15 +1426,18 @@ impl OfficialUpdateService {
         report.local_manifest_verified_count = final_audit.verified_count();
         report.local_manifest_repair_needed_count = final_audit.repair_needed_count();
         report.verification_summary = final_verification_summary;
-        report.snapshot_written = Some(final_snapshot_path.clone());
-        let completed_record = version_state_guard.record()?.clone();
-        complete_version_state(
+        report.snapshot_written = snapshot_written.then(|| final_snapshot_path.clone());
+        if let Err(error) = complete_version_state(
             &version_state_path,
             completed_record,
             &published_version_path,
             &final_snapshot_path,
-        )?;
-        version_state_guard.commit();
+        ) {
+            progress(OfficialUpdateProgress::new(
+                "publish",
+                format!("资源已发布，但写入版本状态失败（下轮可重试）：{error}"),
+            ));
+        }
 
         progress(OfficialUpdateProgress::new(
             "finish",