feat(build-plan): customer_portal goal syncs reservations to Seam on create/change

[itelo]

Summary

End-to-end testing of a customer-portal integration surfaced a gap: the generated code pushed a reservation to Seam only lazily — inside the reservation's deep-link page, i.e. when someone opened it. Nothing pushed on create/change, so a brand-new booking never reached the portal until its access page was visited.

Root cause is the goal: it said "push the reservation, then create a deep-linked portal", which the agent implemented as a per-page-visit push. This adds an explicit sync instruction to composeGoal's customer_portal branch:

Keep Seam in sync with the app: call customers.pushData from the booking create and update handlers (and customers.deleteData on cancellation) so new and changed reservations reach the portal — do not push only when a reservation page is opened.

Behavior preserved

• Still names the framework (…'s conventions).
• Still emits no build-block hint lines for customer_portal (the existing test asserts this).

Testing

• Render check: goal contains customers.pushData, customers.deleteData, Customer Portal, <framework>'s conventions; 0 hint lines
• build-plan.test.ts — all pass
• prettier clean (the only tsc error is @seamapi/cli unresolvable in my local install; CI resolves it)
• Re-run the wizard and confirm the generated booking create/update handlers call pushData

Security & Compliance

• No security impact