feat: developer access permission gates webhooks/API keys/BYOK (v0.71.0)

Webhooks, self-serve API keys, and BYOK AI provider keys had zero
access gating -- any logged-in user, any tier. Adds users.isDeveloper
(boolean, admin-toggled in admin/users/[id] alongside role/tier),
checked via a single hasDeveloperAccess() (lib/permissions.ts) so a
future subscription-tier auto-grant is a one-line change there, not
a redesign across call sites.

requireDeveloper() (lib/api-auth.ts) wraps requireSession() with a
fresh isDeveloper check (same reasoning as requireAdmin re-querying
role: session.user's cookieCache can be up to 5 minutes stale) and
replaces requireSession in all 8 gated routes: webhooks CRUD +
deliveries + redeliver, api-keys CRUD, ai-keys CRUD.

Settings UI: the sidebar hides API Keys/Webhooks nav entries for
non-developers; those pages and the BYOK section of Settings -> AI
show a locked notice instead of the manager component when accessed
directly.

Migration grandfathers in anyone who already has a webhook, API key,
or BYOK key row -- ships as a new gate on existing features, not a
silent lockout of active integrations.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/(app)/settings/webhooks/page.tsx

@@ -1,8 +1,9 @@
 import type { Metadata } from "next";
 import { headers } from "next/headers";
 import { auth } from "@/lib/auth/server";
-import { db, webhooks, eq } from "@epicure/db";
+import { db, webhooks, users, eq } from "@epicure/db";
 import { WebhooksManager } from "@/components/settings/webhooks-manager";
+import { DeveloperLockedNotice } from "@/components/settings/developer-locked-notice";
 import { getMessages } from "@/lib/i18n/server";
 
 export const metadata: Metadata = {};
@@ -12,16 +13,20 @@ export default async function WebhooksPage() {
   if (!session) return null;
   const m = getMessages((session.user as { locale?: string }).locale);
 
-  const rows = await db
-    .select({
-      id: webhooks.id,
-      url: webhooks.url,
-      events: webhooks.events,
-      active: webhooks.active,
-      createdAt: webhooks.createdAt,
-    })
-    .from(webhooks)
-    .where(eq(webhooks.userId, session.user.id));
+  const dbUser = (await db.select({ isDeveloper: users.isDeveloper }).from(users).where(eq(users.id, session.user.id)).limit(1))[0];
+
+  const rows = dbUser?.isDeveloper
+    ? await db
+        .select({
+          id: webhooks.id,
+          url: webhooks.url,
+          events: webhooks.events,
+          active: webhooks.active,
+          createdAt: webhooks.createdAt,
+        })
+        .from(webhooks)
+        .where(eq(webhooks.userId, session.user.id))
+    : [];
 
   return (
     <div className="space-y-8">
@@ -32,15 +37,18 @@ export default async function WebhooksPage() {
             {m.settings.webhooksPage.description}
           </p>
         </div>
-        <WebhooksManager
-          initialWebhooks={rows.map((w) => ({
-            id: w.id,
-            url: w.url,
-            events: w.events,
-            active: w.active,
-            createdAt: w.createdAt.toISOString(),
-          }))}
-        />
+        {!dbUser?.isDeveloper && <DeveloperLockedNotice message={m.settings.developerLockedNotice} />}
+        {dbUser?.isDeveloper && (
+          <WebhooksManager
+            initialWebhooks={rows.map((w) => ({
+              id: w.id,
+              url: w.url,
+              events: w.events,
+              active: w.active,
+              createdAt: w.createdAt.toISOString(),
+            }))}
+          />
+        )}
       </section>
     </div>
   );