📝 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/cpp/.clang-format

@@ -0,0 +1,47 @@
+---
+Language: Cpp
+BasedOnStyle: Google
+
+# Keep consistent with the repo-wide 100 char guidance (adjust per-project if needed).
+ColumnLimit: 100
+
+AccessModifierOffset: -4
+AlignEscapedNewlines: Left
+AlignTrailingComments: false
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortFunctionsOnASingleLine: All
+AlwaysBreakTemplateDeclarations: Yes
+BinPackArguments: false
+BinPackParameters: false
+BraceWrapping:
+  AfterCaseLabel: true
+  AfterUnion: true
+  AfterExternBlock: false
+BreakBeforeTernaryOperators: false
+BreakConstructorInitializers: AfterColon
+BreakInheritanceList: AfterColon
+CommentPragmas: "suppress"
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+Cpp11BracedListStyle: false
+FixNamespaceComments: false
+IncludeBlocks: Regroup
+IncludeCategories:
+  - Regex: '^.*(precomp|pch|stdafx)'
+    Priority: -1
+  - Regex: '^".*"'
+    Priority: 1
+  - Regex: '^<.*>'
+    Priority: 2
+  - Regex: '.*'
+    Priority: 3
+KeepEmptyLinesAtTheStartOfBlocks: false
+MacroBlockBegin: "BEGIN_TEST_METHOD_PROPERTIES|BEGIN_MODULE|BEGIN_TEST_CLASS|BEGIN_TEST_METHOD"
+MacroBlockEnd: "END_TEST_METHOD_PROPERTIES|END_MODULE|END_TEST_CLASS|END_TEST_METHOD"
+NamespaceIndentation: All
+PointerAlignment: Left
+ReflowComments: false
+SortIncludes: false
+SpaceAfterTemplateKeyword: false
+SpacesInAngles: false
+SpacesInContainerLiterals: false
+