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

pyproject.toml

@@ -0,0 +1,38 @@
+[build-system]
+requires = ["setuptools>=64", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "dcos"
+version = "1.0.0"
+description = "Distributed Cognitive Operating System — multi-agent cognitive architecture"
+readme = "README.md"
+requires-python = ">=3.11"
+dependencies = [
+    "pyyaml>=6.0",
+    "pydantic>=2.0",
+]
+[project.optional-dependencies]
+dev = [
+    "pytest>=7.0",
+    "pytest-asyncio>=0.21",
+    "pytest-cov>=4.0",
+    "ruff>=0.1",
+]
+
+[project.scripts]
+dcos = "dcos.utils.cli:main"
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "I"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+pythonpath = ["src"]