📝 docs(playbook): add contributing and multi-language standards

Introduce C++ and Python docs/templates and split .agents rulesets by language (tsl/cpp/python).

Move commit message guidance to CONTRIBUTING.md (full spec remains in docs/common/commit_message.md).

templates/python/.vscode/settings.json

@@ -0,0 +1,14 @@
+{
+  "editor.formatOnSave": true,
+  "editor.rulers": [80],
+  "[python]": {
+    "editor.defaultFormatter": "ms-python.black-formatter",
+    "editor.codeActionsOnSave": {
+      "source.organizeImports": "explicit"
+    }
+  },
+  "python.analysis.typeCheckingMode": "basic",
+  "python.analysis.autoImportCompletions": true,
+  "python.formatting.provider": "none"
+}
+