feat: add new get started mcp resource (#127)

**Context**
As part of our onboarding devx, we want to add a set of steps and
instructions to help users integrate their existing projects with Neon.
We added this guide in
neondatabase-labs/ai-rules#11. This will be
through an `init` command that sets up the MCP server for the user.

**What changes are proposed in this pull request?**
This PR adds the 'get started' AI rule as an MCP server resource. The
user should be able to trigger it by typing 'Get started with Neon' in
the AI assistant chat.

**How was this tested?**
Verified new resource on MCP inspector
<img width="529" height="561" alt="Screenshot 2025-10-31 at 15 58 49"
src="https://github.com/user-attachments/assets/3520ace7-24f0-4154-9b9a-de161eae302a"
/>

#[LKB-4026](https://databricks.atlassian.net/browse/LKB-5291)

Author: shijurodhaz

src/resources.ts

@@ -70,4 +70,24 @@ export const NEON_RESOURCES = [
       };
     },
   },
+  {
+    name: 'neon-get-started',
+    uri: 'https://github.com/neondatabase-labs/ai-rules/blob/main/neon-get-started.mdc',
+    mimeType: 'text/markdown',
+    description: 'Neon getting started guide',
+    handler: async (url) => {
+      const uri = url.host;
+      const rawPath = url.pathname;
+      const content = await fetchRawGithubContent(rawPath);
+      return {
+        contents: [
+          {
+            uri,
+            mimeType: 'text/markdown',
+            text: content,
+          },
+        ],
+      };
+    },
+  },
 ] satisfies (Resource & { handler: ReadResourceCallback })[];