Add OpenAPI spec validation hook (Redocly CLI)

PostToolUse hook triggers on openapi/*.yaml edits and runs
redocly lint with the recommended ruleset (security-defined
disabled since endpoints are intentionally public).

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

.claude/settings.json

@@ -13,6 +13,11 @@
             "type": "command",
             "command": "\"$CLAUDE_PROJECT_DIR/.claude/hooks/frontend-check.sh\"",
             "timeout": 120
+          },
+          {
+            "type": "command",
+            "command": "\"$CLAUDE_PROJECT_DIR/.claude/hooks/openapi-validate.sh\"",
+            "timeout": 120
           }
         ]
       }