fix: resolve rebase conflicts, fix errcheck issues, implement FetchAndDecryptBlob

internal/vaultik/blobcache.go

@@ -167,7 +167,7 @@ func (c *blobDiskCache) ReadAt(key string, offset, length int64) ([]byte, error)
 	if err != nil {
 		return nil, err
 	}
-	defer f.Close()
+	defer func() { _ = f.Close() }()
 
 	buf := make([]byte, length)
 	if _, err := f.ReadAt(buf, offset); err != nil {