Add configurable beta test plans and staged rollout

src/routes/api/betas/presets/+server.ts

@@ -0,0 +1,18 @@
+import { json } from '@sveltejs/kit';
+import { db } from '$lib/server/db/index.js';
+import { builtInPlans, parseBetaPlan } from '$lib/beta-plan.js';
+export function GET() {
+    const saved = db().prepare('SELECT name, plan FROM beta_test_presets ORDER BY name').all() as Array<{ name: string; plan: string }>;
+    return json({ presets: [...builtInPlans, ...saved.map(p => ({ name: p.name, plan: JSON.parse(p.plan) }))] });
+}
+export async function POST({ request }: { request: Request }) {
+    try {
+        const body = await request.json();
+        if (typeof body.name !== 'string' || !body.name.trim() || body.name.length > 80) throw new Error('Preset name must be 1–80 characters');
+        if (builtInPlans.some(p => p.name === body.name.trim())) throw new Error('Choose a name other than a built-in preset');
+        const plan = parseBetaPlan(body.plan);
+        db().prepare('INSERT INTO beta_test_presets (name, plan) VALUES (?, ?) ON CONFLICT(name) DO UPDATE SET plan = excluded.plan')
+            .run(body.name.trim(), JSON.stringify(plan));
+        return json({ ok: true });
+    } catch (error) { return json({ ok: false, error: (error as Error).message }, { status: 400 }); }
+}