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_memory/test_world_model.py

@@ -0,0 +1,35 @@
+"""
+Tests for WorldModel.
+"""
+
+import pytest
+from dcos.memory.world_model import WorldModel
+
+
+class TestWorldModel:
+    def test_add_and_get_entity(self):
+        model = WorldModel()
+        model.add_entity("e1", {"type": "robot", "status": "active"})
+        entity = model.get_entity("e1")
+        assert entity is not None
+        assert entity["properties"]["type"] == "robot"
+
+    def test_update_entity(self):
+        model = WorldModel()
+        model.add_entity("e1", {"status": "inactive"})
+        model.update_entity("e1", {"status": "active"})
+        entity = model.get_entity("e1")
+        assert entity["properties"]["status"] == "active"
+
+    def test_set_and_get_state(self):
+        model = WorldModel()
+        model.set_state("phase", "exploration")
+        assert model.get_state("phase") == "exploration"
+
+    def test_query_entities(self):
+        model = WorldModel()
+        model.add_entity("drone1", {"type": "drone", "team": "alpha"})
+        model.add_entity("drone2", {"type": "drone", "team": "beta"})
+        model.add_entity("robot1", {"type": "robot", "team": "alpha"})
+        drones = model.query_entities("type", "drone")
+        assert len(drones) == 2