Connect Share: turn every invite into a one-click install and join

[robinbraemer]

Human need

Receiving an invite should never turn into researching loaders, versions, dependencies, or where to paste a custom URI. The invitation itself should carry the recipient from “I want to join” to the correct running game.

Outcome

Every Connect Share invite has an HTTPS handoff that offers an immediate vanilla join when possible, selects the correct mod artifact and launcher when richer features are needed, and resumes the original invite after installation.

Acceptance criteria

• A normal HTTPS link accompanies every custom-protocol invitation.
• The page explains the human action—join a friend—before mentioning installation.
• Minecraft version, loader, operating system, and supported launcher choices are resolved without exposing tokens or private addressing.
• Modrinth App, PrismLauncher, CurseForge, and manual download paths are supported where their platforms permit it.
• Required dependencies install automatically.
• The original signed invitation survives launcher installation/restart and resumes exactly once.
• A recipient who already has the mod opens directly into the confirmation/join flow.
• A recipient who declines installation still receives the ordinary Direct Connect path when the host enabled it.
• Expired, revoked, incompatible, or malicious invitations have safe, actionable states.
• Invite previews use concise social copy and never reveal endpoint tokens, private keys, local/public IPs, or hidden presence.
• Funnel measurement is opt-in and contains no friend graph or invitation secret.
• TDD and browser/launcher E2E cover supported operating systems, launchers, cancellation, retries, and install-resume.

Product metric

Percentage of invite recipients who successfully appear in the host world, segmented by already-installed, newly-installed, and vanilla paths.

Parent: #93

[robinbraemer]

Repository contract completed in 20e439b: fragment-only invitation transport, local validation, safe launcher resolution, vanilla fallback, one-shot install resume, malicious/expired/revoked states, privacy boundary, and cross-OS browser/launcher E2E matrix. The client intentionally does not emit a dead HTTPS link. This issue remains open because the reviewed handoff web app/origin, published marketplace projects, launcher adapters, resume implementation, and deployed log/referrer evidence are external and do not exist in this repository.