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_working.py

@@ -0,0 +1,42 @@
+"""
+Tests for WorkingMemory.
+"""
+
+import pytest
+from dcos.memory.working import WorkingMemory
+
+
+class TestWorkingMemory:
+    def test_store_and_recall(self):
+        mem = WorkingMemory()
+        mem.store("key1", "value1")
+        assert mem.recall("key1") == "value1"
+
+    def test_overwrite(self):
+        mem = WorkingMemory()
+        mem.store("k", "v1")
+        mem.store("k", "v2")
+        assert mem.recall("k") == "v2"
+
+    def test_missing_key(self):
+        mem = WorkingMemory()
+        assert mem.recall("nonexistent") is None
+
+    def test_contains(self):
+        mem = WorkingMemory()
+        mem.store("present", "data")
+        assert mem.contains("present") is True
+        assert mem.contains("absent") is False
+
+    def test_clear(self):
+        mem = WorkingMemory()
+        mem.store("a", 1)
+        mem.store("b", 2)
+        mem.clear()
+        assert mem.size() == 0
+
+    def test_capacity(self):
+        mem = WorkingMemory(capacity=5)
+        for i in range(10):
+            mem.store(f"key{i}", i)
+        assert mem.size() <= 5