S00-003: Record blocked task and remediation handoff

Changes: Preserve incomplete work and blocker metadata for S00-003. This checkpoint does not mark implementation accepted.
Validation: Session ended with status blocked.
Blocker: S00-003 cannot attest parser limits: Stanza 12.22.1 exposes no resource bounds and its persistent WebSocket parser accepts large/deep XML and reassembles incomplete documents across separate input messages.

Task: S00-003
Agent: auto-protocol-902594b44429
Role: protocol
Action: claim
Status: blocked

Task title: Проверить XMPP WSS/auth библиотеку

experiments/0002-xmpp-library/parser-probe/reproduce.mjs

@@ -0,0 +1,57 @@
+// Bounded diagnostic of the stock parser; passing means the defect reproduced.
+// No network, credentials, vendor patch, or production implementation.
+import assert from 'node:assert/strict';
+import {createRequire} from 'node:module';
+const require = createRequire(import.meta.url);
+const Client = require('stanza/Client').default;
+const {StreamParser} = require('stanza/jxt');
+assert.equal(require('stanza/package.json').version, '12.22.1');
+const tick = () => new Promise(resolve => setImmediate(resolve));
+function harness() {
+  const client = new Client({autoReconnect: false});
+  // Same parser options as shipped transports/websocket.js.
+  const parser = new StreamParser({registry: client.stanzas,
+    wrappedStream: false, allowComments: false});
+  const received = [], errors = [];
+  parser.on('data', value => received.push(value));
+  parser.on('error', error => errors.push(error));
+  return {parser, received, errors};
+}
+const opening = '<message xmlns="jabber:client"><body>';
+const closing = '</body></message>';
+
+const split = harness();
+split.parser.write(opening);
+for (let i = 0; i < 16; i++) split.parser.write('a'.repeat(4096));
+await tick();
+assert.equal(split.errors.length, 0);
+assert.equal(split.received.length, 0);
+assert.equal(split.parser.destroyed, false);
+split.parser.write(closing);
+await tick();
+assert.equal(split.errors.length, 0);
+assert.equal(split.received.length, 1);
+assert.equal(split.received[0].stanza.body.length, 65536);
+split.parser.destroy();
+console.log('stock: 18 separate writes reassembled into one 65536-byte body; no error');
+
+const large = harness();
+large.parser.write(opening + 'b'.repeat(1048576) + closing);
+await tick();
+assert.equal(large.errors.length, 0);
+assert.equal(large.received.length, 1);
+assert.equal(large.received[0].stanza.body.length, 1048576);
+large.parser.destroy();
+console.log('stock: 1048576-byte body accepted; no error');
+
+const deep = harness();
+deep.parser.write('<message xmlns="jabber:client">' + '<x>'.repeat(256) +
+  '</x>'.repeat(256) + '</message>');
+await tick();
+assert.equal(deep.errors.length, 0);
+assert.equal(deep.received.length, 1);
+let element = deep.received[0].xml, depth = 0;
+while (element.children[0]) {element = element.children[0]; depth++;}
+assert.equal(depth, 256);
+deep.parser.destroy();
+console.log('stock: 256 nested child elements accepted; no error');