Add .clang-format

.clang-format

@@ -0,0 +1,30 @@
+---
+# Prism coding style — enforced by clang-format.
+# Conventions that cannot be automated (e.g. return-type alignment
+# across declarations) are documented in AGENTS.md.
+
+BasedOnStyle: LLVM
+
+# Indentation — tabs (no spaces)
+UseTab: Always
+IndentWidth: 8
+TabWidth: 8
+
+# Braces — always required after if/else/for/while/do
+AllowShortFunctionsOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+BreakBeforeBraces: Attach
+
+# Pointer/reference alignment — * against name not type
+PointerAlignment: Right
+ReferenceAlignment: Right
+
+# Continuation lines — align with first parameter after (
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+
+# Line width
+ColumnLimit: 120
+PenaltyReturnTypeOnItsOwnLine: 1000