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_learning/test_engine.py

@@ -0,0 +1,25 @@
+"""
+Tests for LearningEngine.
+"""
+
+import pytest
+from dcos.learning.engine import LearningEngine, Experience
+
+
+class TestLearningEngine:
+    def test_record_experience(self):
+        engine = LearningEngine()
+        engine.record_experience(Experience(state={}, action="move", reward=1.0))
+        assert engine.experience_count() == 1
+
+    def test_best_action(self):
+        engine = LearningEngine()
+        engine.record_experience(Experience(state={}, action="a", reward=10))
+        engine.record_experience(Experience(state={}, action="b", reward=5))
+        best = engine.best_action(["a", "b"])
+        assert best == "a"
+
+    def test_get_action_score(self):
+        engine = LearningEngine()
+        engine.record_experience(Experience(state={}, action="explore", reward=0.5))
+        assert engine.get_action_score("explore") == 0.05  # 0.5 * 0.1