Add GitHub starred-list filtering with searchable selector (#247)

* feat: add starred list filtering and selector UI

* docs: add starred lists UI screenshot

* lib: improve starred list name matching

src/pages/api/github/starred-lists.ts

@@ -0,0 +1,53 @@
+import type { APIRoute } from "astro";
+import { db, configs } from "@/lib/db";
+import { eq } from "drizzle-orm";
+import {
+  createGitHubClient,
+  getGithubStarredListNames,
+} from "@/lib/github";
+import { getDecryptedGitHubToken } from "@/lib/utils/config-encryption";
+import { jsonResponse, createSecureErrorResponse } from "@/lib/utils";
+import { requireAuthenticatedUserId } from "@/lib/auth-guards";
+
+export const GET: APIRoute = async ({ request, locals }) => {
+  try {
+    const authResult = await requireAuthenticatedUserId({ request, locals });
+    if ("response" in authResult) return authResult.response;
+    const userId = authResult.userId;
+
+    const [config] = await db
+      .select()
+      .from(configs)
+      .where(eq(configs.userId, userId))
+      .limit(1);
+
+    if (!config) {
+      return jsonResponse({
+        data: { success: false, message: "No configuration found for this user" },
+        status: 404,
+      });
+    }
+
+    if (!config.githubConfig?.token) {
+      return jsonResponse({
+        data: { success: false, message: "GitHub token is missing in config" },
+        status: 400,
+      });
+    }
+
+    const token = getDecryptedGitHubToken(config);
+    const githubUsername = config.githubConfig?.owner || undefined;
+    const octokit = createGitHubClient(token, userId, githubUsername);
+    const lists = await getGithubStarredListNames({ octokit });
+
+    return jsonResponse({
+      data: {
+        success: true,
+        lists,
+      },
+      status: 200,
+    });
+  } catch (error) {
+    return createSecureErrorResponse(error, "starred lists fetch", 500);
+  }
+};