Add Claude Code hooks and release skill

- PostToolUse hook: auto-format .rs files with rustfmt after edit
- PreToolUse hook: block direct edits to Cargo.lock
- /release skill: build .deb and inspect package metadata

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude/hooks/format-rs.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+# Auto-format Rust files after Edit/Write
+INPUT=$(cat)
+FILE_PATH=$(echo "$INPUT" | jq -r '.tool_input.file_path // empty')
+
+if [[ "$FILE_PATH" == *.rs ]]; then
+    rustfmt --edition 2021 "$FILE_PATH" 2>/dev/null || true
+fi