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_agents/test_planning.py

@@ -0,0 +1,32 @@
+"""
+Tests for PlanningAgent.
+"""
+
+import pytest
+from dcos.agents.planning import PlanningAgent
+from dcos.agents.base import AgentRole
+
+
+class TestPlanningAgent:
+    def test_initialization(self):
+        agent = PlanningAgent()
+        assert agent.identity.name == "planner"
+        assert agent.identity.role == AgentRole.PLANNER
+
+    def test_act_returns_plan(self):
+        agent = PlanningAgent()
+        result = agent.act({"goal": "test_goal"})
+        assert "plan" in result
+        assert "steps" in result
+
+    def test_decompose_goal(self):
+        agent = PlanningAgent()
+        tasks = agent.decompose("complex_goal")
+        assert len(tasks) > 0
+        assert tasks[0]["id"] == "research"
+
+    def test_capabilities(self):
+        agent = PlanningAgent()
+        caps = agent.get_capabilities()
+        assert "strategic_planning" in caps
+        assert "task_decomposition" in caps