feat(lander): integrate persistent insert & get lsm store

lsm/include/lsm/store.h

@@ -17,7 +17,8 @@
  */
 typedef enum lsm_attr_type : uint64_t {
   lsm_attr_type_entry_type = 1 << 0,
-  lsm_attr_type_content_type = 1 << 1
+  lsm_attr_type_content_type = 1 << 1,
+  lsm_attr_type_url = 1 << 2,
 } lsm_attr_type;
 
 /**

lsm/src/store/lsm_store_disk_write.c

@@ -100,6 +100,9 @@ lsm_error lsm_entry_sync(lsm_store *store, lsm_entry_handle *handle) {
     res = lsm_entry_write_uint64_t(store->idx_file, new_block_count);
 
     if (res == lsm_error_ok) {
+      // Only if we successfully updated the on-disk counter do we make the code
+      // aware that the file's size has increased. This way, if a write to the
+      // counter fails, the code will simply reuse the already written content.
       store->idx_file_size += entry_size;
       store->idx_file_block_count = new_block_count;
     }