chore: clean up content phase organization

apps/docs/blume.config.ts

@@ -1,5 +1,5 @@
 import { defineConfig } from "blume";
-
+import { filesystem, githubReleases } from "blume/sources";
 import redirects from "./redirects";
 
 // Blume's defaults (`inter`, `ibm-plex-mono`) are fetched from fonts.gstatic.com
@@ -44,7 +44,14 @@ export default defineConfig({
   lastModified: "git",
   redirects,
   content: {
-    root: "content",
+    sources: [
+      filesystem({ root: "content" }),
+      githubReleases({
+        prefix: "changelog",
+        owner: "prdlk",
+        repo: "leetcode",
+      }),
+    ],
   },
   theme: {
     fonts: { display: inter, body: inter, mono: plexMono },