Add scheduled Bible reading sessions with subscriber management

[KallynGowdy]

Summary

This PR adds support for creating and managing scheduled shared Bible reading sessions in Discord. Users can launch sessions for a specific book/chapter at a scheduled time, and other users can subscribe via emoji reactions to receive personalized links when the session starts.

Key Changes

Core Session Management

• New SessionStore trait in store/store.rs defining operations for creating, retrieving, and managing scheduled sessions
• Database schema (migration/m20260819_000000_create_scheduled_sessions.rs) with two new tables:
  • scheduled_sessions: stores session metadata (UUID, guild/channel/creator IDs, book, chapter, scheduled time, reminder settings, status)
  • scheduled_session_subscribers: tracks which users have subscribed to each session via emoji reactions
• Sea-orm entities for both tables with proper relationships and constraints

Implementation

• FakeStore in-memory implementation with test helpers (with_scheduled_session builder method) and comprehensive test suite
• SqliteStore production implementation using sea-orm for all CRUD operations
• Session lifecycle management:
  • Create sessions with auto-incrementing IDs and UUID for sharing
  • Track announcement message IDs for reaction-based subscription
  • Mark reminders as sent and sessions as started
  • List pending sessions for scheduler bootstrap

User-Facing Features

• /launchsession slash command with modal UI collecting:
  • Book name and chapter number
  • When to start ("now" or "YYYY-MM-DD HH:MM" UTC)
  • Optional reminder lead time in minutes
• Two session modes:
  • "Now" sessions: immediately provide creator with personalized link (no announcement/subscription flow)
  • Scheduled sessions: post announcement in channel, allow others to subscribe via 📖 emoji reactions
• Reaction handlers (handler/reaction.rs) for adding/removing subscribers when users react with 📖

Scheduling & Jobs

• Job scheduler integration (session/scheduler.rs) using tokio_cron_scheduler:
  • Register start and reminder jobs for each session
  • Bootstrap pending sessions on bot startup (survives restarts)
  • Dynamically compute delays from absolute scheduled_at timestamps
• Job implementations (session/jobs.rs):
  • Start job: posts personalized links for all subscribers (each in their preferred language/translation)
  • Reminder job: pings subscribers N minutes before start

Utilities

• Time parsing (session/time_parse.rs): validates "now" or future UTC datetime strings
• Reminder parsing: validates positive integer minute values
• Session URL builder (util/format.rs): generates seedbible.org links with sessionId parameter for collaborative sessions
• Reply builders (poise_impl/replies.rs): ephemeral confirmations and public announcements with proper formatting

Notable Implementation Details

• Session UUIDs are globally unique and placed in the seedbible.org sessionId query parameter to auto-create shared sessions
• Each subscriber receives a personalized link respecting their individual language/translation preferences
• Reminder and start jobs are one-shot async tasks with computed delays, allowing sessions to survive bot restarts
• Duplicate subscriber additions are prevented at the database level (unique constraint) and application level
• All session state transitions (pending → started) are persisted to prevent duplicate job execution

https://claude.ai/code/session_01KmHj65AfgKRPCtVPpyxcSZ