Connect Share: follow a friend into their next joinable world

[robinbraemer]

Human need

When somebody wants to spend time with a friend, they should not need to watch presence, coordinate in Discord, or repeatedly click refresh. They should be able to express the intent once: join this friend when they are ready.

Recommended first experience: Follow Next Session

• A player chooses Join Robin when available.
• The intent is one-shot and expires after joining, logout, cancellation, or a bounded time.
• When Robin enters a joinable world, Connect Share automatically sends the join request.
• If Robin has explicitly enabled Auto-Accept for that friend, admission happens automatically.
• Otherwise Robin receives the normal approval notification.
• Before leaving the current menu/session, the follower sees a short cancelable notification.
• Connect Share never pulls somebody out of an active world or server; it offers Join Now instead.

Later relationship permission

Always Follow may be enabled only with clear consent and matching host access policy. It is not the default.

Safety and privacy

• Following does not reveal presence the follower could not already see.
• Blocking, removal, hidden presence, or Never Allow cancels pending follow intent.
• Offline and unreachable states time out without repeated spam.
• Every automatic transition is visible and cancelable.
• No transport details are exposed.

Acceptance criteria

• Follow intent persists safely across title-screen and menu transitions.
• At most one join request is emitted for a world-presence epoch.
• Repeated presence updates cannot create request storms.
• Auto-accept requires an explicit per-friend host policy.
• Active gameplay is never interrupted automatically.
• Both sides receive understandable notifications.
• TDD covers expiry, cancellation, reconnect, removal, blocks, duplicate presence, and simultaneous follow.

Product metric

Percentage of Follow Next Session intents that end with both friends playing together, and median time from the host becoming joinable to guest admission.

Parent epic: #93

[robinbraemer]

Repository-owned Follow Next Session is implemented on PR #94 at head 9a0c947.

The one-shot intent persists through menus, expires and cancels safely, emits at most once per world epoch, avoids duplicate storms, retries only for a new epoch, cancels on removal/block/hidden state, never interrupts active gameplay, and requires explicit Auto-Accept host policy before automatic admission. TDD covers expiry, cancellation, reconnect, removal, blocks, duplicates, and simultaneous follow.

This issue remains open for exact packaged-client UX proof across title/menu transitions, the Join Now offer during active gameplay, both-side notifications, and visible cancellation copy. The full Gradle build and all eight CI jobs pass.