[P0] Private beta user journey: first login, connect account, compose and schedule first post

[yacosta738]

Objective

Validate the invited-user happy path for the private beta from invitation acceptance through the first successful publish-now or scheduled post.

Classification

• INCOMPLETE private-beta user journey work.
• Publishing/scheduling remains USER_REPORTED_OPERATIONAL on the VPS.
• This does not claim provider-verified, production-verified, or multi-user-verified capability.

Scope

• Cover invitation acceptance.
• Cover first-login redirect.
• Cover new workspace empty state.
• Cover connect/reconnect.
• Cover compose.
• Cover optional media.
• Cover publish now.
• Cover schedule.
• Cover calendar feedback.
• Cover timezone behavior.
• Cover status feedback.
• Cover missing connection.
• Cover expired credentials.
• Cover rate limits.
• Cover provider failures.
• Cover worker-disabled state.
• Keep Community Management, imported posts, comments, and replies hidden or explicitly marked unavailable.

Definition of done

• A fresh invitee can accept an invitation, land in the correct first-login flow, and reach a usable empty workspace state.
• Account connect/reconnect, compose, optional media, publish-now, and schedule flows are understandable and usable.
• Calendar feedback, status feedback, and timezone behavior are clear.
• Missing connection, expired credentials, rate limits, provider failures, and worker-disabled state produce actionable feedback.
• Community Management, imported posts, comments, and replies remain hidden or clearly unavailable.
• Focused unit and end-to-end coverage is green.
• Evidence remains limited to the tested account/workspace and does not claim multi-user verification.

Dependencies

• Depends on [P0] Private beta release gate: VPS publishing/scheduling evidence, rollback and support runbook #651 and [P0] Private beta invite and activation operations #652.
• Does not depend on [Discovery] Validate LinkedIn Community Management API access and operating constraints #563, [Operations] Add webhook ingestion and Standard Tier provider-event activation #571, [Backend] Implement production R2DBC calendar cursor continuation #612, [Architecture] Complete schema-backed social content evidence and checkpoints #613, or [Privacy] Build the retention, deletion and backup-expiry engine #349.

[linear-code]

DALLAY-558