fix: harden long conversation continuity

mindspace-workspace-sync.mjs

@@ -302,11 +302,17 @@ export function createWorkspaceAssetSync({
       if (!space || space.status !== 'active') {
         throw Object.assign(new Error('用户空间不可用'), { code: 'space_unavailable' });
       }
-      const sizeDelta = buffer.length - asNumber(existing.size_bytes);
-      const available =
-        asNumber(space.quota_bytes) - asNumber(space.used_bytes) - asNumber(space.reserved_bytes);
-      if (sizeDelta > 0 && available < sizeDelta) {
-        throw Object.assign(new Error('剩余空间不足'), { code: 'quota_exceeded' });
+      const [assetRows] = await conn.query(
+        `SELECT id, current_version_id, size_bytes, checksum
+         FROM h5_assets
+         WHERE id = ? AND user_id = ?
+         LIMIT 1
+         FOR UPDATE`,
+        [existing.id, userId],
+      );
+      const currentAsset = assetRows[0];
+      if (!currentAsset) {
+        throw Object.assign(new Error('工作区资产不存在'), { code: 'asset_not_found' });
       }
 
       const detectedMimeType = assetInternals.detectMimeType(buffer, file.filename);
@@ -321,19 +327,36 @@ export function createWorkspaceAssetSync({
       const assetStatus = assetStatusForScan(scan);
       const versionScanStatus = versionStatusForScan(scan);
       const checksum = crypto.createHash('sha256').update(buffer).digest('hex');
-      const [versionRows] = await conn.query(
-        `SELECT COALESCE(MAX(version_no), 0) AS max_version
-         FROM h5_asset_versions
-         WHERE asset_id = ?`,
-        [existing.id],
-      );
-      const versionNo = asNumber(versionRows[0]?.max_version) + 1;
-      const versionId = idFactory();
       const finalStorageKey = buildWorkspaceStorageKey(
         userId,
         category.category_code,
         file.filename,
       );
+      if (currentAsset.checksum === checksum) {
+        await conn.commit();
+        return {
+          action: 'skipped',
+          assetId: currentAsset.id,
+          filename: file.filename,
+          checksum,
+          mimeType: detectedMimeType,
+          sizeBytes: buffer.length,
+          storageKey: finalStorageKey,
+          categoryCode: category.category_code,
+        };
+      }
+      const sizeDelta = buffer.length - asNumber(currentAsset.size_bytes);
+      const available =
+        asNumber(space.quota_bytes) - asNumber(space.used_bytes) - asNumber(space.reserved_bytes);
+      if (sizeDelta > 0 && available < sizeDelta) {
+        throw Object.assign(new Error('剩余空间不足'), { code: 'quota_exceeded' });
+      }
+      const versionId = currentAsset.current_version_id;
+      if (!versionId) {
+        throw Object.assign(new Error('工作区资产版本不存在'), {
+          code: 'asset_version_missing',
+        });
+      }
 
       const now = Date.now();
       const indexedWorkspacePath = resolveAssetWorkspaceRelativePath({
@@ -342,11 +365,10 @@ export function createWorkspaceAssetSync({
       });
       await conn.query(
         `UPDATE h5_assets
-         SET current_version_id = ?, size_bytes = ?, checksum = ?, mime_type = ?,
+         SET size_bytes = ?, checksum = ?, mime_type = ?,
              asset_type = ?, risk_level = ?, status = ?, workspace_relative_path = ?, updated_at = ?
          WHERE id = ? AND user_id = ?`,
         [
-          versionId,
           buffer.length,
           checksum,
           detectedMimeType,
@@ -360,21 +382,19 @@ export function createWorkspaceAssetSync({
         ],
       );
       await conn.query(
-        `INSERT INTO h5_asset_versions
-         (id, asset_id, version_no, storage_key, size_bytes, checksum, mime_type,
-          created_by, change_note, scan_status, created_at)
-         VALUES (?, ?, ?, ?, ?, ?, ?, ?, '工作区文件更新', ?, ?)`,
+        `UPDATE h5_asset_versions
+         SET size_bytes = ?, checksum = ?, mime_type = ?, created_by = ?,
+             change_note = '工作区文件更新', scan_status = ?, created_at = ?
+         WHERE id = ? AND asset_id = ?`,
         [
-          versionId,
-          existing.id,
-          versionNo,
-          finalStorageKey,
           buffer.length,
           checksum,
           detectedMimeType,
           userId,
           versionScanStatus,
           now,
+          versionId,
+          currentAsset.id,
         ],
       );
       if (sizeDelta !== 0) {
@@ -387,7 +407,7 @@ export function createWorkspaceAssetSync({
       await conn.commit();
       return {
         action: 'updated',
-        assetId: existing.id,
+        assetId: currentAsset.id,
         filename: file.filename,
         checksum,
         mimeType: detectedMimeType,
@@ -484,8 +504,15 @@ export function createWorkspaceAssetSync({
       }
       if (existing) {
         const result = await updateWorkspaceFile(userId, category, existing, file, buffer);
+        if (result.action === 'skipped') {
+          existing.checksum = checksum;
+          existing.size_bytes = buffer.length;
+          skipped += 1;
+          continue;
+        }
         await registerWorkspaceArtifactForConversation(userId, source, result);
         existing.checksum = checksum;
+        existing.size_bytes = buffer.length;
         updated += 1;
       } else {
         const result = await importWorkspaceFile(userId, category, file, buffer);