feat(platform-api): multi-audience JWT + Partner CRUD + tenant lifecycle (O.2)

JwtAuthGuard now accepts a comma-separated AUTHENTIK_AUDIENCE
('dezky-portal,dezky-operator'). jose.jwtVerify takes an array and succeeds
on any match — both customer-portal and operator-portal tokens validate
against this service. Per-endpoint guards restrict further.

New OperatorGuard enforces operator-only mutations:
  1. JWT audience claim includes 'dezky-operator' (proof from the token
     alone that this is a privileged session)
  2. ActorService-resolved User has platformAdmin=true (DB check so
     revocation works without waiting for the token to expire)
Both required; either alone is insufficient.

Partner module:
  - Partner schema: slug, name, domain, status, marginPct, contactInfo,
    billingInfo. marginPct is one number per partner (decided in grilling)
  - CRUD endpoints under @UseGuards(JwtAuthGuard, OperatorGuard) — every
    partner mutation requires operator scope
  - GET /partners returns each row with a computed customers count from
    aggregating Tenant.partnerId. MRR aggregation deferred until
    Subscription gains a price column
  - GET /partners/:slug/tenants for the partner detail view
  - DELETE soft-terminates (status='terminated') — never hard-delete
    because tenants may still reference the partner

Tenant changes:
  - partnerId?: Types.ObjectId (ref Partner, indexed sparse) added to
    Tenant schema
  - UpdateTenantDto accepts partnerId so PATCH can attach/detach
  - POST /tenants/:slug/suspend and /resume — operator-only via
    OperatorGuard. PATCH already covers plan/domains/partnerId changes

Smoke test: customer-portal session sends POST /api/partners through the
portal proxy → 403 "This endpoint requires an operator-scoped token". The
positive test (operator-token → 200) waits for O.3 when there's an
operator app to mint the right token.

apps/portal/server/api/partners/index.post.ts is a temporary verification
proxy — delete once the operator portal exists.

apps/portal/server/api/partners/index.post.ts

@@ -0,0 +1,27 @@
+// Temporary proxy used only to verify O.2's audience-gating from the browser.
+// This forwards the customer-portal session's access token — which has aud
+// 'dezky-portal' — to platform-api's POST /partners. We expect 403 because
+// that endpoint requires aud='dezky-operator'. Delete this file once the
+// operator portal exists and the real (positive) test runs from there.
+
+import { getUserSession } from 'nuxt-oidc-auth/runtime/server/utils/session.js'
+
+export default defineEventHandler(async (event) => {
+  const session = await getUserSession(event).catch(() => null)
+  const accessToken = (session as { accessToken?: string } | null)?.accessToken
+  if (!accessToken) {
+    throw createError({ statusCode: 401, statusMessage: 'Not signed in' })
+  }
+  const body = await readBody(event)
+  const base = process.env.PLATFORM_API_INTERNAL_URL ?? 'http://platform-api:3001'
+  try {
+    return await $fetch(`${base}/partners`, {
+      method: 'POST',
+      headers: { Authorization: `Bearer ${accessToken}` },
+      body,
+    })
+  } catch (err: unknown) {
+    const e = err as { statusCode?: number; data?: unknown }
+    throw createError({ statusCode: e.statusCode ?? 500, data: e.data })
+  }
+})