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

src/dcos/communication/network.py

@@ -0,0 +1,46 @@
+"""
+Communication network — manages agent connectivity and message delivery.
+"""
+
+from __future__ import annotations
+from typing import Any, Dict, List, Optional
+from .protocol import Message, CommunicationProtocol
+
+
+class CommunicationNetwork:
+    """Manages the topology and message delivery between agents."""
+
+    def __init__(self) -> None:
+        self._protocol = CommunicationProtocol()
+        self._connections: Dict[str, List[str]] = {}  # agent_id -> [peer_ids]
+        self._message_log: List[Message] = []
+
+    def connect(self, agent_a: str, agent_b: str) -> None:
+        self._connections.setdefault(agent_a, []).append(agent_b)
+        self._connections.setdefault(agent_b, []).append(agent_a)
+
+    def disconnect(self, agent_a: str, agent_b: str) -> None:
+        for peer in (agent_a, agent_b):
+            if peer in self._connections:
+                self._connections[peer] = [
+                    p for p in self._connections[peer] if p != agent_b
+                ]
+
+    def deliver(self, message: Message) -> bool:
+        if message.recipient in self._connections.get(message.sender, []):
+            self._message_log.append(message)
+            return self._protocol.send(message)
+        return False
+
+    def broadcast(self, sender: str, payload: Any) -> int:
+        peers = self._connections.get(sender, [])
+        for peer in peers:
+            msg = Message(sender=sender, recipient=peer, payload=payload)
+            self._message_log.append(msg)
+        return len(peers)
+
+    def get_peers(self, agent_id: str) -> List[str]:
+        return self._connections.get(agent_id, [])
+
+    def get_message_log(self, limit: int = 100) -> List[Message]:
+        return self._message_log[-limit:]