Default new trial accounts to Home screen, agent, and new social-media connections

Make the Home screen, the agent, and the new social-media connections the default experience for all new trial accounts.

## Goal

Every newly created trial account should land in and use the new surfaces by default:

* Home screen as the entry point / dashboard.
* Agent (agentic CaptureFlow) as the primary content workflow.
* New social-media connections (latest connection flow, e.g. Zernio-backed where applicable) for linking accounts.

## Scope

* Ensure trial signups are provisioned so Home, agent, and the new social connections are enabled by default (e.g. the relevant per-workspace flags such as agent_v2 / new-connections are on for new trials).
* Route new trial users to the Home screen as the default landing experience.
* Use the new social-media connection flow for trial accounts rather than any legacy path.
* Confirm onboarding and first-run experience reflect these defaults.

## Notes

* Applies to NEW trial accounts only; do not change existing accounts unless intended.
* Verify gating/feature-flag defaults at the point of trial creation.

## Acceptance

* A brand-new trial account starts on the Home screen, can use the agent, and connects social accounts via the new flow, with no manual flag flipping required.