feat: discover all recent Unity versions from releases page, not just latest

Improves version discovery to capture all recent versions from Unity's official
releases page instead of just the latest one. This ensures versions like 6000.3.17f1
are added to the system within minutes of release, allowing reconciliation to build
and publish images responsively without manual intervention.

**What changed:**
- New function scrapeRecentOfficialUnityVersions() captures all versions found on
  the releases page using regex matching and fallback changeset extraction
- scrapeLatestOfficialUnityVersion() now delegates to the new function for compatibility
- scrapeVersions() merges all recent discovered versions into the main list alongside
  unity-changeset library results, respecting deduplication

**Why:**
Previously, the fallback only grabbed the absolute latest version. If 6000.4.10f1 was
latest, 6000.3.17f1 would be missed. Now all recent releases are captured, so
reconciliation can begin building immediately after discovery, within 15 minutes.

**Rate limits:**
- No additional API calls beyond existing Unity releases page fetch
- Already-discovered versions via unity-changeset library not re-queried
- Deduplication prevents duplicate entries

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: frostebite

functions/src/logic/ingestUnityVersions/scrapeVersions.ts

@@ -31,7 +31,7 @@ const toEditorVersionInfo = (unityVersion: UnityChangesetVersion): EditorVersion
   } as EditorVersionInfo;
 };
 
-export const scrapeLatestOfficialUnityVersion = async (): Promise<EditorVersionInfo | null> => {
+export const scrapeRecentOfficialUnityVersions = async (): Promise<EditorVersionInfo[]> => {
   const response = await fetch(unity_whats_new_url, {
     redirect: 'follow',
     headers: {
@@ -44,21 +44,38 @@ export const scrapeLatestOfficialUnityVersion = async (): Promise<EditorVersionI
   }
 
   const html = await response.text();
-  const versionMatch = /Unity\s+(\d+\.\d+\.\d+f\d+)/.exec(html);
-  const escapedVersion = versionMatch?.[1].replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
-  const changesetMatch = versionMatch
-    ? new RegExp(`unityhub://${escapedVersion}/([a-f0-9]{12})`, 'i').exec(html) ||
-      /Changeset:\s*([a-f0-9]{12})/i.exec(html)
-    : null;
-
-  if (!versionMatch || !changesetMatch) {
-    return null;
+  const versions: UnityChangesetVersion[] = [];
+  const processedVersions = new Set<string>();
+
+  const versionRegex = /(\d+\.\d+\.\d+f\d+)/g;
+  let match;
+  while ((match = versionRegex.exec(html)) !== null) {
+    const version = match[1];
+    if (processedVersions.has(version)) continue;
+    processedVersions.add(version);
+
+    const escapedVersion = version.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    const changesetMatch =
+      new RegExp(`unityhub://${escapedVersion}/([a-f0-9]{12})`, 'i').exec(html) ||
+      new RegExp(`${escapedVersion}[^a-f0-9]*([a-f0-9]{12})`, 'i').exec(html) ||
+      /Changeset:\s*([a-f0-9]{12})/i.exec(html);
+
+    if (changesetMatch?.[1]) {
+      versions.push({
+        version,
+        changeset: changesetMatch[1],
+      });
+    }
   }
 
-  return toEditorVersionInfo({
-    version: versionMatch[1],
-    changeset: changesetMatch[1],
-  });
+  return versions
+    .map(toEditorVersionInfo)
+    .filter((versionInfo): versionInfo is EditorVersionInfo => versionInfo !== null);
+};
+
+export const scrapeLatestOfficialUnityVersion = async (): Promise<EditorVersionInfo | null> => {
+  const recentVersions = await scrapeRecentOfficialUnityVersions();
+  return recentVersions.length > 0 ? recentVersions[0] : null;
 };
 
 export const scrapeVersions = async (): Promise<EditorVersionInfo[]> => {
@@ -74,7 +91,7 @@ export const scrapeVersions = async (): Promise<EditorVersionInfo[]> => {
       changeset,
     }),
   );
-  const latestOfficialVersion = await scrapeLatestOfficialUnityVersion();
+  const recentOfficialVersions = await scrapeRecentOfficialUnityVersions();
 
   // Merge XLTS versions into main list, avoiding duplicates
   const existingVersions = new Set(unityVersions.map((v) => v.version));
@@ -85,11 +102,15 @@ export const scrapeVersions = async (): Promise<EditorVersionInfo[]> => {
     }
   }
 
-  if (latestOfficialVersion && !existingVersions.has(latestOfficialVersion.version)) {
-    unityVersions.push({
-      version: latestOfficialVersion.version,
-      changeset: latestOfficialVersion.changeSet,
-    });
+  // Merge recent official versions discovered from Unity releases page
+  for (const officialVersion of recentOfficialVersions) {
+    if (!existingVersions.has(officialVersion.version)) {
+      unityVersions.push({
+        version: officialVersion.version,
+        changeset: officialVersion.changeSet,
+      });
+      existingVersions.add(officialVersion.version);
+    }
   }
 
   if (unityVersions?.length > 0) {