0.4.0

Site-initiated pairing. The site now starts pairing: @feralfile/play creates the channel and shows the visitor an app link (button on a phone, QR on a desktop) and a six-digit code; the Feral File app brings their Art Computer to it. Owners can keep a site paired until they remove it in the app.

Breaking (integrators calling requestEphemeralSession directly): the pairing input ({ shortCode } / { qrPayload }) is gone, along with parsePairingQrPayload and pairingToResolved; pass onPairingMaterial({ appLink, shortCode, expiresAt }) instead. createPairingCodeDialog is now createPairingDialog. PlayErrorCode drops pairing_code_not_found and pairing_code_used. mountPlayOnArtComputerButton is unchanged apart from an optional appLinkBaseUrl. Guide: docs/integration.md.

Also in this release:

• The site's request rides the create call, so the Art Computer can ask its owner as soon as it joins (FF OS releases carrying ffos-user#375); earlier devices keep working through the encrypted request (#17, #19).
• A session the Art Computer delivered while the page was suspended is collected instead of discarded (#19).
• A cast that fails once on a network error is retried once (#19).
• No pairing link or code is shown after a cancel that lands during channel creation (#16, #18).

Requires the Mint Pairing Broker at play c31c2ea or later (live on handoff.feralfile.com). 0.3.x sites keep working.