fix(docs-site): migrate to astro v6 content collections config (#6451)

* fix(docs-site): migrate to astro v6 content collections config

Astro v6 removed legacy content collections. 'astro check'/'astro build'
failed with LegacyContentConfigError because the config lived at
src/content/config.ts without a collection loader.

- Move src/content/config.ts -> src/content.config.ts
- Add Starlight docsLoader() to the docs collection

Verified: 'npm run build' (astro check && astro build) now completes.

* fix(deps): bump brace-expansion to 5.0.7 to fix ReDoS advisory

Adds a brace-expansion >=5.0.7 override to resolve GHSA-3jxr-9vmj-r5cp
(DoS via exponential-time expansion of consecutive non-expanding {} groups),
which was failing the 'Audit Main Package' npm audit --audit-level=high gate.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 7ef9f0e7-1882-478d-90c0-6e4d42313685

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: 3 people

docs-site/src/content/config.ts docs-site/src/content.config.tsdocs-site/src/content/config.ts renamed to docs-site/src/content.config.ts

@@ -1,6 +1,7 @@
 import { defineCollection } from 'astro:content';
+import { docsLoader } from '@astrojs/starlight/loaders';
 import { docsSchema } from '@astrojs/starlight/schema';
 
 export const collections = {
-  docs: defineCollection({ schema: docsSchema() }),
+  docs: defineCollection({ loader: docsLoader(), schema: docsSchema() }),
 };

package-lock.json

@@ -80,7 +80,8 @@
   },
   "overrides": {
     "test-exclude": "^7.0.1",
-    "minimatch": ">=10.2.1"
+    "minimatch": ">=10.2.1",
+    "brace-expansion": ">=5.0.7"
   },
   "engines": {
     "node": ">=20.19.0"