feat: refine and finalize redesign

src/utils/versions.ts

@@ -0,0 +1,48 @@
+import { getCollection } from "astro:content";
+import * as semver from "semver";
+import { config } from "../config";
+
+export interface VersionInfo {
+  versions: string[];
+  currentVersion: string;
+}
+
+/**
+ * Get version information derived from available spec files.
+ * Returns all versions sorted newest-first and determines the current version.
+ */
+export async function getVersionInfo(): Promise<VersionInfo> {
+  const specs = await getCollection("spec");
+  const versions = specs
+    .map((s) => s.data.version)
+    .filter((v): v is string => semver.valid(v) !== null)
+    .sort((a, b) => semver.rcompare(a, b)); // newest first
+
+  const currentVersion =
+    config.currentVersionOverride ?? determineCurrentVersion(versions);
+
+  return { versions, currentVersion };
+}
+
+/**
+ * Determine the current version based on priority:
+ * 1. Latest stable version
+ * 2. Latest RC version
+ * 3. Newest available version
+ */
+function determineCurrentVersion(versions: string[]): string {
+  // Priority order: stable (null prerelease) first, then rc
+  const priority: (string | null)[] = [null, "rc"];
+
+  for (const type of priority) {
+    const match = versions.find((v) => {
+      const pre = semver.prerelease(v);
+      if (type === null) return pre === null;
+      return pre?.[0] === type;
+    });
+    if (match) return match;
+  }
+
+  // Fallback to newest overall
+  return versions[0] ?? "";
+}