Add /sandboxing standalone reference page + update agentic-devops tool card link

* Initial plan

* Create /sandboxing reference page and update agentic-devops tool card link

Co-authored-by: htekdev <100806365+htekdev@users.noreply.github.com>
Agent-Logs-Url: https://github.com/htekdev/htek-dev-site/sessions/c494e4ce-24f7-46a1-a753-02754212a300

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: htekdev <100806365+htekdev@users.noreply.github.com>

Author: Copilot

src/pages/agentic-devops.astro

@@ -62,7 +62,7 @@ const tools = [
     name: 'Agent Sandboxes',
     category: 'Execution Isolation',
     description: 'Policy-governed sandbox environments where agents operate safely. Kernel-level filesystem, network, and process isolation that makes rule-breaking structurally impossible.',
-    link: '/articles/sandboxes-missing-infrastructure-layer-agentic-devops',
+    link: '/sandboxing',
   },
 ];