RespondKit v0.3.0

RespondKit 0.3.0 adds unread reply notifications and verified customer history.

• The chat launcher checks for operator replies every 10 seconds while the browser tab is visible, including while chat is closed, and shows a red dot for unread replies across authorized conversations.
• Read state persists across reloads and synchronizes between tabs. Opening a conversation acknowledges the loaded transcript; other conversations remain unread.
• Persistent browser identities preserve anonymous conversations. A signed backend identity assertion links them to an account and restores history after signing in on another browser. PostHog IDs remain advisory aliases.
• Auth transitions isolate history, and session credentials renew after switching conversations.

Packages: @respondkit/protocol@0.3.0, @respondkit/api-client@0.3.0, and @respondkit/react@0.3.0.

The API must be deployed before upgrading the widget. Account linking additionally requires matching per-inbox signing keys on RespondKit and the product backend, plus getIdentityToken / identityPending in the integration. See the identity setup guide.

Includes #19 and #20. Validated with 175 tests, app and SDK builds, and clean npm consumer checks. Live visual browser QA was unavailable.