feat: implement DCOS source tree, tests, and build configuration

Complete implementation of the DCOS package including:
- 40+ Python source files across agents, communication, core, learning, memory, protocols, utils
- pyproject.toml build configuration
- 102 unit tests across all subsystems
- Fixed flake.nix (Python 3.12, proper dependencies, pyproject build)
- Fixed .woodpecker.yml (correct paths, removed silent-fail flags)
- Added .gitignore
- Cleared stale pytest cache

tests/test_communication/test_protocol.py

@@ -0,0 +1,26 @@
+"""
+Tests for CommunicationProtocol.
+"""
+
+import pytest
+from dcos.communication.protocol import CommunicationProtocol, Message
+
+
+class TestCommunicationProtocol:
+    def test_encode_decode(self):
+        proto = CommunicationProtocol()
+        msg = Message(sender="alice", recipient="bob", payload="hello")
+        encoded = proto.encode(msg)
+        assert encoded["sender"] == "alice"
+        assert encoded["recipient"] == "bob"
+
+        decoded = proto.decode(encoded)
+        assert decoded.payload == "hello"
+
+    def test_send_and_ack(self):
+        proto = CommunicationProtocol()
+        msg = Message(sender="a", recipient="b", payload="data")
+        assert proto.send(msg) is True
+        ack = proto.ack(msg.msg_id)
+        assert ack is not None
+        assert ack.msg_id == msg.msg_id