[Docs] Update MCP instructions and AI integration documentation

This commit enhances the documentation for the Stack Auth MCP server by clarifying the usage of the `ask_stack_auth` tool and the skill resource. The instructions now emphasize the importance of using `ask_stack_auth` for accessing official documentation and troubleshooting, while also detailing the role of the `skill` resource for quick references. These updates aim to improve user guidance and streamline the integration process.

Author: mantrakp04

apps/mcp/src/mcp-handler.ts

@@ -176,7 +176,7 @@ export function createStackMcpHandler(config: { streamableHttpEndpoint: string }
         name: "stack-auth-mcp",
         version: packageJson.version,
       },
-      instructions: "Stack Auth's official MCP server. Use the `ask_stack_auth` tool for any question about Stack Auth — setup, SDKs (Next.js, React, JS), APIs, configuration, OAuth, teams/permissions, or troubleshooting. The tool searches the official docs and answers with citations. Prefer it over web search or guessing from training data, since Stack Auth changes frequently.",
+      instructions: "Stack Auth's official MCP server. Prefer the `ask_stack_auth` tool for any question about Stack Auth — setup, SDKs (Next.js, React, JS), APIs, configuration, OAuth, teams/permissions, or troubleshooting. It searches the official docs and answers with citations, and should be your first stop over web search or training data since Stack Auth changes frequently. The `skill` resource/tool loads SKILL.md (the canonical Stack Auth agent skill) — pull it in when you need a quick reference for project setup, CLI usage, or wiring conventions, but always use `ask_stack_auth` first.",
     },
     {
       streamableHttpEndpoint: config.streamableHttpEndpoint,

docs-mintlify/guides/getting-started/ai-integration.mdx

@@ -98,7 +98,7 @@ Install the skill once so your agent loads it automatically every time Stack Aut
 
 ## Option 2: MCP
 
-The Stack Auth MCP server (`https://mcp.stack-auth.com/mcp`) gives your agent live access to Stack Auth docs and an `ask_stack_auth` tool that searches the docs with citations. Install it once per agent — it stays available across every project.
+The Stack Auth MCP server (`https://mcp.stack-auth.com/mcp`) gives your agent live access to Stack Auth docs and skill via prompts, resources and an `ask_stack_auth` tool that searches the docs with citations. Install it once per agent — it stays available across every project.
 
 <Tabs>
   <Tab title="One-click install">