chore: add Husky hooks to prevent Claude Code from bad git practices (#10937)

- Adds two Husky hooks to prevent Claude Code from bad git practices:
  - \`prepare-commit-msg\`: blocks \`git commit --amend\` (detected via the \`commit\` source argument)
  - \`pre-commit\`: blocks committing directly to \`main\`
- Both hooks detect Claude Code sessions via the \`CLAUDECODE\` environment variable, so regular users are unaffected
- Error messages explicitly tell Claude what to do instead

.husky/pre-commit

@@ -0,0 +1,7 @@
+#!/bin/sh
+# Prevent Claude Code from committing directly on the main branch.
+
+if [ -n "$CLAUDECODE" ] && [ "$(git rev-parse --abbrev-ref HEAD)" = "main" ]; then
+  echo "error: Committing directly to the main branch is not allowed. Create a new branch and open a pull request instead." >&2
+  exit 1
+fi

.husky/prepare-commit-msg

@@ -0,0 +1,8 @@
+#!/bin/sh
+# Prevent Claude Code from amending commits.
+# The prepare-commit-msg hook receives "commit" as $2 when --amend is used.
+
+if [ "$2" = "commit" ] && [ -n "$CLAUDECODE" ]; then
+  echo "error: Amending commits is not allowed. Create a new commit instead." >&2
+  exit 1
+fi