Add pre-commit hook for cargo fmt check

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: madeye

.githooks/pre-commit

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+if ! cargo fmt -- --check 2>/dev/null; then
+    echo "Error: cargo fmt check failed. Run 'cargo fmt' and stage the changes."
+    exit 1
+fi

CLAUDE.md

@@ -2,6 +2,12 @@
 
 This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
 
+## Setup
+
+```bash
+git config core.hooksPath .githooks   # enable pre-commit fmt check
+```
+
 ## Build Commands
 
 ```bash

README.md

@@ -121,6 +121,16 @@ Commands:
 4. Authenticated CONNECT requests → TCP tunnel via HTTP upgrade + bidirectional copy
 5. Authenticated HTTP requests → forwarded to upstream with proxy headers stripped
 
+## Development
+
+After cloning, enable the pre-commit hook to catch formatting issues before they reach CI:
+
+```bash
+git config core.hooksPath .githooks
+```
+
+The hook runs `cargo fmt --check` and blocks commits with unformatted code.
+
 ## Testing
 
 ```bash