Refresh script library with batch uploads and beta handoff

src/routes/betas/+page.svelte

@@ -4,6 +4,7 @@
     import { onMount, onDestroy } from 'svelte';
     import { artifactVersionLabel } from '$lib/artifact-version.js';
     import { goto } from '$app/navigation';
+    import { parseBetaSelection } from '$lib/script-library.js';
     import Card from '$ui/components/primitives/Card.svelte';
     import Badge from '$ui/components/primitives/Badge.svelte';
     import Button from '$ui/components/primitives/Button.svelte';
@@ -61,6 +62,7 @@
             fetch('/api/scripts'),
             fetch('/api/servers')
         ]);
+        if (!betasRes.ok || !scriptsRes.ok || !serversRes.ok) throw new Error('Could not load beta setup. Refresh to try again.');
         const bBody = (await betasRes.json()) as { betas: BetaListRow[] };
         betas = bBody.betas;
         if (scriptsRes.ok) {
@@ -71,7 +73,6 @@
             const svBody = (await serversRes.json()) as { servers: ServerRow[] };
             fleetServers = svBody.servers;
         }
-        loading = false;
     }
     async function refreshBetas(): Promise<void> {
         const res = await fetch('/api/betas');
@@ -82,7 +83,7 @@
 
     let poll: ReturnType<typeof setInterval> | null = null;
     onMount(() => {
-        void load().then(seedImportedPlugin).catch(error => { flash = (error as Error).message; });
+        void load().then(seedSelection).catch(error => { flash = (error as Error).message; }).finally(() => { loading = false; });
         poll = setInterval(refreshBetas, 5000);
     });
     onDestroy(() => {
@@ -91,7 +92,8 @@
 
     const eligibleScripts = $derived(
         scripts.filter(
-            (s) => s.runningBetaId === null && s.latestVersion !== null && s.latestVersion.id !== s.current_version_id
+            (s) => s.runningBetaId === null && s.latestVersion !== null && (s.latestVersion.id !== s.current_version_id
+                || picks.some(p => p.scriptId === s.id && p.versionId !== null && p.versionId !== s.current_version_id))
         )
     );
 
@@ -102,24 +104,26 @@
         return eligibleScripts.filter((s) => !takenIds.has(s.id));
     }
 
-    async function seedImportedPlugin(): Promise<void> {
+    async function seedSelection(): Promise<void> {
         const query = new URLSearchParams(window.location.search);
-        if (!query.has('pluginId')) return;
-        const pluginId = Number(query.get('pluginId'));
-        const versionId = Number(query.get('versionId'));
-        if (!eligibleScripts.some(s => s.id === pluginId && s.kind === 'plugin')) {
-            flash = 'This plugin is already promoted or has a running beta. Open its detail page to review its status.';
-            return;
+        const selections = parseBetaSelection(query);
+        if (!selections.length) return;
+        // Validate all selections before populating; never substitute a newer upload.
+        const details = await Promise.all(selections.map(async ({ scriptId, versionId }) => {
+            const res = await fetch(`/api/scripts/${scriptId}`);
+            if (!res.ok) throw new Error('A selected artifact is no longer available. Choose artifacts below.');
+            const detail = await res.json() as ScriptDetail & { runningBetaId: number | null };
+            if (detail.runningBetaId !== null || detail.script.current_version_id === versionId
+                || !detail.versions.some(v => v.id === versionId)) {
+                throw new Error(`${detail.script.name}: the selected version is already promoted, unavailable, or in an active beta. Review your selection below.`);
+            }
+            return detail;
+        }));
+        for (const detail of details) {
+            detailById[detail.script.id] = detail;
         }
-        picks = [{ key: nextKey++, scriptId: pluginId, versionId: null }];
-        await onPickScript(0);
-        if (!versionsForRow(picks[0]).some(v => v.id === versionId)) {
-            picks[0].versionId = null;
-            flash = 'The imported version is no longer available for testing. Choose a version to continue.';
-            return;
-        }
-        picks[0].versionId = versionId;
-        picks = [...picks];
+        picks = selections.map(s => ({ key: nextKey++, ...s }));
+        pickedServers = new Set();
     }
 
     async function onPickScript(rowIdx: number): Promise<void> {
@@ -246,6 +250,8 @@
         subtitle="Test unpromoted versions on selected servers before rolling them out."
     />
 
+    {#if flash}<p class="flash" role="alert">{flash}</p>{/if}
+
     {#if loading}
         <div class="loading">Loading…</div>
     {:else}
@@ -336,7 +342,6 @@
                         >
                             Open beta
                         </Button>
-                        {#if flash}<span class="flash">{flash}</span>{/if}
                     </div>
                 </form>
             {/if}