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

flake.nix

@@ -10,25 +10,34 @@
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = nixpkgs.legacyPackages.${system};
-        python = pkgs.python311;
-        pythonPackages = pkgs.python311Packages;
+        python = pkgs.python312;
+        pythonPackages = pkgs.python312Packages;
       in {
         packages.default = pythonPackages.buildPythonPackage {
           pname = "dcos";
           version = "1.0.0";
           src = ./.;
-          nativeBuildInputs = with pkgs; [
+          nativeBuildInputs = with pythonPackages; [
             python
-            pyyaml
+            setuptools
+            wheel
           ];
           propagatedBuildInputs = with pythonPackages; [
             pyyaml
+            pydantic
           ];
-          doCheck = false;
-          format = "pyproject";
+          doCheck = true;
+          checkInputs = with pythonPackages; [
+            pytest
+            pytest-asyncio
+          ];
+          checkPhase = ''
+            pytest tests/ -x --tb=short -q
+          '';
           pyproject = true;
           pyprojectFiles = [ "pyproject.toml" ];
           makeWheel = true;
+          packageDir = "src";
         };
 
         devShells.default = pkgs.mkShell {
@@ -38,10 +47,12 @@
             pythonPackages.pytest
             pythonPackages.pytest-asyncio
             pythonPackages.pyyaml
+            pythonPackages.pydantic
+            pythonPackages.ruff
           ];
           shellHook = ''
-            export PYTHONPATH="${toString (builtins.toPath ./src)}:$PYTHONPATH"
-            echo "DCOS dev shell — Python 3.11, pytest, pyyaml"
+            export PYTHONPATH="${toString ./src}:$PYTHONPATH"
+            echo "DCOS dev shell — Python 3.12, pytest, pyyaml, pydantic"
           '';
         };
       });