FIX: MessageBus reconnect reliability

[merefield]

• Reworked live status updates to be MessageBus-first, with notification and PM badges seeded from Discourse’s notification_channel_position instead of relying on steady-state HTTP polling.
• Replaced constant healthy-state badge polling with reconnect-triggered one-shot HTTP resync, while keeping HTTP fallback when live counts are still unseeded or MessageBus is unavailable.
• Added per-channel MessageBus cursor tracking for /latest, /new, /unread, /unread/:user_id, /notification/:user_id, and active /topic/:id subscriptions.
• Added a MessageBus watchdog that runs every 30s, detects stale clients after 240s without successful polls, and rebuilds the client cleanly.
• Added reconnect recovery that restores subscriptions from saved channel positions and requests list/topic refreshes when resume state is not trustworthy.
• Introduced a timeout-configured MessageBusHTTPClient wrapper with explicit open, read, and write timeouts.
• Fixed reconnect edge cases so badge seeding keeps retrying until live values are populated, and default -1 cursors are treated as non-resumable rather than trusted.
• Added live topic subscriptions for /topic/:id, so termcourse can react while you are inside a topic instead of only at the list level.
• Added live in-topic handling for new posts, including tail-follow behavior when you are already on the last loaded post.
• Added live in-topic handling for post edits, likes/unlikes, delete/recover-style updates via targeted single-post refreshes.
• Added topic refresh fallback for reload-style and stats-style topic events when incremental updates are not sufficient.
• Fixed topic reconnect behavior so revisiting a topic updates the stored topic cursor and failed topic refreshes stay pending until they succeed.
• Improved topic-view responsiveness by removing constant idle rerenders, rendering only the needed visible post blocks, caching rendered post blocks, and reducing debug I/O churn.
• Tightened temporary debug instrumentation so it is only active when TERMCOURSE_DEBUG=1.
• Clarified auth behavior in the README: realtime MessageBus features require login auth with a session cookie; API-key auth is HTTP-only and does not support live PM/topic updates.
• Added focused regression coverage for reconnect reliability, resumable cursors, topic refresh behavior, healthy-state no-poll behavior, and the custom MessageBus HTTP client wrapper.

[Copilot]

Pull request overview

This PR reworks Termcourse’s live status updates to be MessageBus-first, improving reconnect behavior and reducing steady-state HTTP polling by seeding counts from the server and resyncing on reconnect.

Changes:

• Added watchdog-driven MessageBus reconnect logic with per-channel resume positions and explicit resync/refresh requests.
• Made notification + PM badge counts primarily driven by MessageBus, with HTTP seeding/resync and reduced periodic polling.
• Introduced a timeout-configured MessageBus HTTP client wrapper and expanded test coverage for the new behaviors.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
lib/termcourse/live_updates.rb	Adds watchdog/restart logic, per-channel positions, resync + topic list refresh requests, and PM count tracking.
lib/termcourse/message_bus_http_client.rb	New MessageBus HTTP client subclass to apply explicit Net::HTTP timeouts for long-polling.
lib/termcourse/ui.rb	Switches UI loops to maybe_refresh_status_counts, adds server seeding/resync hooks, and integrates PM unread via live updates.
lib/termcourse/cli.rb	Passes notification_channel_position from Discourse session/current-user data into the UI.
lib/termcourse.rb	Requires the new message_bus_http_client file.
test/live_updates_test.rb	Adds tests for resume positions, channel position tracking, watchdog restarts, and refresh requests.
test/ui_caching_test.rb	Updates caching/polling tests to reflect “live healthy => no poll” and reconnect resync behavior; adds PM totals coverage.
test/ui_renderer_test.rb	Extends notification state tests to cover PM unread count behavior when live values are zero.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

This PR shifts termcourse’s realtime model to be MessageBus-first (instead of steady-state polling), improves reconnect reliability, and extends realtime behavior into topic view with live post updates plus fallback resync/refresh paths.

Changes:

• Reworks status counts (notifications + PMs) to prefer MessageBus values, with one-shot HTTP reseeding on reconnect and reduced background polling.
• Adds MessageBus reliability features: per-channel positions, watchdog-based stale detection/restart, and a timeout-configured MessageBus HTTP client wrapper.
• Adds topic-view live-update plumbing (watching topic channels, merging post deltas, and cache invalidation) plus README clarification about realtime requiring cookie-based login auth.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
test/ui_renderer_test.rb	Updates UI notification-state tests for PM unread counts and new refresh return shape.
test/ui_caching_test.rb	Updates caching/status-count tests for MessageBus-first behavior, reseed retry, and reconnect resync.
test/live_updates_test.rb	Expands LiveUpdates tests for channel positions, watchdog restarts, and reseed triggers.
lib/termcourse/ui.rb	Implements MessageBus-first status counts, reconnect resync hooks, topic live-update loop, and post-block caching/invalidation.
lib/termcourse/message_bus_http_client.rb	Introduces a timeout-configured MessageBus HTTP client with streaming long-poll handling.
lib/termcourse/live_updates.rb	Adds watchdog/restart logic, per-channel cursor tracking, PM unread tracking, and reconnect resync signaling.
lib/termcourse/cli.rb	Passes Discourse’s notification_channel_position into UI/LiveUpdates setup.
lib/termcourse.rb	Wires in the new MessageBus HTTP client wrapper.
README.md	Documents realtime limitations of API-key auth and clarifies status badge behavior.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.