chore: remove unused buildBlocksBytes method

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Co-Authored-By: Claude Opus 4.5 <[e-mail]>

src/pds.js

···
     return blocks
   }
 
-  // Build CAR-style block bytes (without header, just block entries)
-  buildBlocksBytes(blocks) {
-    const parts = []
-    for (const block of blocks) {
-      const cidBytes = block.cid instanceof Uint8Array ? block.cid : cidToBytes(block.cid)
-      const blockLen = cidBytes.length + block.data.length
-      // Varint encode the length
-      let len = blockLen
-      while (len >= 0x80) {
-        parts.push((len & 0x7f) | 0x80)
-        len >>= 7
-      }
-      parts.push(len)
-      parts.push(...cidBytes)
-      parts.push(...block.data)
-    }
-    return new Uint8Array(parts)
-  }
-
   async createRecord(collection, record, rkey = null) {
     const did = await this.getDid()
     if (!did) throw new Error('PDS not initialized')