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/components/admin/user-editor.tsx

@@ -11,16 +11,19 @@ import {
   SelectValue,
 } from "@/components/ui/select";
 import { Label } from "@/components/ui/label";
+import { Switch } from "@/components/ui/switch";
 
 interface UserEditorProps {
   userId: string;
   currentRole: "user" | "moderator" | "admin";
   currentTier: "free" | "pro" | "family";
+  currentIsDeveloper: boolean;
 }
 
-export function UserEditor({ userId, currentRole, currentTier }: UserEditorProps) {
+export function UserEditor({ userId, currentRole, currentTier, currentIsDeveloper }: UserEditorProps) {
   const [role, setRole] = useState<"user" | "moderator" | "admin">(currentRole);
   const [tier, setTier] = useState<"free" | "pro" | "family">(currentTier);
+  const [isDeveloper, setIsDeveloper] = useState(currentIsDeveloper);
   const [saving, setSaving] = useState(false);
 
   async function handleSave() {
@@ -29,7 +32,7 @@ export function UserEditor({ userId, currentRole, currentTier }: UserEditorProps
       const res = await fetch(`/api/v1/admin/users/${userId}`, {
         method: "PATCH",
         headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({ role, tier }),
+        body: JSON.stringify({ role, tier, isDeveloper }),
       });
       if (!res.ok) {
         const data = await res.json().catch(() => ({}));
@@ -73,6 +76,13 @@ export function UserEditor({ userId, currentRole, currentTier }: UserEditorProps
           </Select>
         </div>
       </div>
+      <div className="flex items-center justify-between gap-3 rounded-lg border p-3 max-w-md">
+        <div>
+          <Label htmlFor="developer-switch">Developer access</Label>
+          <p className="text-xs text-muted-foreground">Enables webhooks, self-serve API keys, and BYOK AI provider keys.</p>
+        </div>
+        <Switch id="developer-switch" checked={isDeveloper} onCheckedChange={setIsDeveloper} />
+      </div>
       <div>
         <Button onClick={handleSave} disabled={saving}>
           {saving ? "Saving…" : "Save Changes"}