Fix: Silence npm output in SessionStart hook to fix context injection

Problem: npm install outputs "up to date in Xms" to stdout, which prepends
non-JSON text to the hook output. Claude Code expects pure JSON and cannot
parse the output, causing context injection to fail silently.

Solution: Changed npm install flag from --loglevel=error to --loglevel=silent
to completely suppress stdout output, ensuring clean JSON output for hook.

Impact: SessionStart hook will now properly inject recent context into sessions.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

plugin/hooks/hooks.json

@@ -6,7 +6,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": "cd \"${CLAUDE_PLUGIN_ROOT}/..\" && npm install --prefer-offline --no-audit --no-fund --loglevel=error && node ${CLAUDE_PLUGIN_ROOT}/scripts/context-hook.js",
+            "command": "cd \"${CLAUDE_PLUGIN_ROOT}/..\" && npm install --prefer-offline --no-audit --no-fund --loglevel=silent && node ${CLAUDE_PLUGIN_ROOT}/scripts/context-hook.js",
             "timeout": 300
           }
         ]