feat(git-flow): add branch name validation hook (#226)

Implements PreToolUse/Bash hook to validate branch naming convention:
- Validates type/description format
- Allowed types: feat, fix, chore, docs, refactor, test, perf, debug
- Enforces lowercase, hyphens, max 50 chars
- Non-branch commands pass through

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/git-flow/hooks/hooks.json

@@ -0,0 +1,19 @@
+{
+  "hooks": {
+    "PreToolUse": [
+      {
+        "matcher": "Bash",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/branch-check.sh"
+          },
+          {
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/commit-msg-check.sh"
+          }
+        ]
+      }
+    ]
+  }
+}