chore: optimize npm keywords for search visibility

Add 11 keywords (mcp-security, claude-code, ai-firewall, etc.) and
front-load search terms in description. Total 29 keywords.

Author: jnMetaCode

package.json

@@ -1,7 +1,7 @@
 {
   "name": "shellward",
   "version": "0.5.9",
-  "description": "AI Agent Security Middleware — 8-layer defense against prompt injection, data exfiltration & dangerous commands. DLP model: use data freely, block external leaks. Zero dependencies. SDK + OpenClaw plugin. Supports LangChain, AutoGPT, Claude Code, Cursor, OpenAI Agents.",
+  "description": "AI agent security & MCP security middleware — prompt injection detection, AI firewall, runtime guardrails & data-loss prevention for LLM tool calls. 8-layer defense against data exfiltration & dangerous commands. Zero dependencies. SDK + OpenClaw plugin. Supports LangChain, AutoGPT, Claude Code, Cursor, OpenAI Agents.",
   "keywords": [
     "shellward",
     "ai-security",
@@ -20,7 +20,18 @@
     "openclaw",
     "sdk",
     "PII",
-    "agent-security"
+    "agent-security",
+    "mcp-security",
+    "mcp",
+    "claude-code",
+    "ai-safety",
+    "ai-firewall",
+    "tool-call-security",
+    "runtime-security",
+    "agent-guard",
+    "data-loss-prevention",
+    "chinese-pii",
+    "injection-detection"
   ],
   "author": "jnMetaCode",
   "license": "Apache-2.0",