feat: add com.atproto.repo.deleteRecord endpoint

Implements record deletion with proper ATProto event emission:
- Removes record from database and rebuilds MST
- Creates signed commit with updated repo state
- Emits delete event to firehose for relay/indexer propagation
- Routes POST requests with repo in body to correct Durable Object

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/pds.js

···
     method: 'POST',
     handler: (pds, req, url) => pds.handleCreateRecord(req)
   },
+  '/xrpc/com.atproto.repo.deleteRecord': {
+    method: 'POST',
+    handler: (pds, req, url) => pds.handleDeleteRecord(req)
+  },
   '/xrpc/com.atproto.repo.getRecord': {
     handler: (pds, req, url) => pds.handleGetRecord(url)
   },
···
     return { uri, cid: recordCidStr, commit: commitCidStr }
   }
 
+  async deleteRecord(collection, rkey) {
+    const did = await this.getDid()
+    if (!did) throw new Error('PDS not initialized')
+
+    const uri = `at://${did}/${collection}/${rkey}`
+
+    // Check if record exists
+    const existing = this.sql.exec(
+      `SELECT cid FROM records WHERE uri = ?`, uri
+    ).toArray()
+    if (existing.length === 0) {
+      return { error: 'RecordNotFound', message: 'record not found' }
+    }
+
+    // Delete from records table
+    this.sql.exec(`DELETE FROM records WHERE uri = ?`, uri)
+
+    // Rebuild MST
+    const mst = new MST(this.sql)
+    const dataRoot = await mst.computeRoot()
+
+    // Get previous commit
+    const prevCommits = this.sql.exec(
+      `SELECT cid, rev FROM commits ORDER BY seq DESC LIMIT 1`
+    ).toArray()
+    const prevCommit = prevCommits.length > 0 ? prevCommits[0] : null
+
+    // Create commit
+    const rev = createTid()
+    const commit = {
+      did,
+      version: 3,
+      data: dataRoot ? new CID(cidToBytes(dataRoot)) : null,
+      rev,
+      prev: prevCommit?.cid ? new CID(cidToBytes(prevCommit.cid)) : null
+    }
+
+    // Sign commit
+    const commitBytes = cborEncodeDagCbor(commit)
+    const signingKey = await this.getSigningKey()
+    const sig = await sign(signingKey, commitBytes)
+
+    const signedCommit = { ...commit, sig }
+    const signedBytes = cborEncodeDagCbor(signedCommit)
+    const commitCid = await createCid(signedBytes)
+    const commitCidStr = cidToString(commitCid)
+
+    // Store commit block
+    this.sql.exec(
+      `INSERT OR REPLACE INTO blocks (cid, data) VALUES (?, ?)`,
+      commitCidStr, signedBytes
+    )
+
+    // Store commit reference
+    this.sql.exec(
+      `INSERT INTO commits (cid, rev, prev) VALUES (?, ?, ?)`,
+      commitCidStr, rev, prevCommit?.cid || null
+    )
+
+    // Update head and rev
+    await this.state.storage.put('head', commitCidStr)
+    await this.state.storage.put('rev', rev)
+
+    // Collect blocks for the event (commit + MST nodes, no record block)
+    const newBlocks = []
+    newBlocks.push({ cid: commitCidStr, data: signedBytes })
+    if (dataRoot) {
+      const mstBlocks = this.collectMstBlocks(dataRoot)
+      newBlocks.push(...mstBlocks)
+    }
+
+    // Sequence event with delete action
+    const eventTime = new Date().toISOString()
+    const evt = cborEncode({
+      ops: [{ action: 'delete', path: `${collection}/${rkey}`, cid: null }],
+      blocks: buildCarFile(commitCidStr, newBlocks),
+      rev,
+      time: eventTime
+    })
+    this.sql.exec(
+      `INSERT INTO seq_events (did, commit_cid, evt) VALUES (?, ?, ?)`,
+      did, commitCidStr, evt
+    )
+
+    // Broadcast to subscribers
+    const evtRows = this.sql.exec(
+      `SELECT * FROM seq_events ORDER BY seq DESC LIMIT 1`
+    ).toArray()
+    if (evtRows.length > 0) {
+      this.broadcastEvent(evtRows[0])
+      // Forward to default DO for relay subscribers
+      if (this.env?.PDS) {
+        const defaultId = this.env.PDS.idFromName('default')
+        const defaultPds = this.env.PDS.get(defaultId)
+        const row = evtRows[0]
+        const evtArray = Array.from(new Uint8Array(row.evt))
+        defaultPds.fetch(new Request('http://internal/forward-event', {
+          method: 'POST',
+          body: JSON.stringify({ ...row, evt: evtArray })
+        })).catch(e => console.log('forward error:', e))
+      }
+    }
+
+    return { ok: true }
+  }
+
   formatEvent(evt) {
     // AT Protocol frame format: header + body
     // Use DAG-CBOR encoding for body (CIDs need tag 42 + 0x00 prefix)
···
     try {
       const result = await this.createRecord(body.collection, body.record, body.rkey)
       return Response.json(result)
+    } catch (err) {
+      return Response.json({ error: err.message }, { status: 500 })
+    }
+  }
+
+  async handleDeleteRecord(request) {
+    const body = await request.json()
+    if (!body.collection || !body.rkey) {
+      return Response.json({ error: 'InvalidRequest', message: 'missing collection or rkey' }, { status: 400 })
+    }
+    try {
+      const result = await this.deleteRecord(body.collection, body.rkey)
+      if (result.error) {
+        return Response.json(result, { status: 404 })
+      }
+      return Response.json({})
     } catch (err) {
       return Response.json({ error: err.message }, { status: 500 })
     }
···
     const id = env.PDS.idFromName(repo)
     const pds = env.PDS.get(id)
     return pds.fetch(request)
+  }
+
+  // POST repo endpoints have repo in body
+  if (url.pathname === '/xrpc/com.atproto.repo.deleteRecord' ||
+      url.pathname === '/xrpc/com.atproto.repo.createRecord') {
+    const body = await request.json()
+    const repo = body.repo
+    if (!repo) {
+      return Response.json({ error: 'InvalidRequest', message: 'missing repo param' }, { status: 400 })
+    }
+    const id = env.PDS.idFromName(repo)
+    const pds = env.PDS.get(id)
+    // Re-create request with body since we consumed it
+    return pds.fetch(new Request(request.url, {
+      method: 'POST',
+      headers: request.headers,
+      body: JSON.stringify(body)
+    }))
   }
 
   const did = url.searchParams.get('did')