Add invite list UI showing registration link status and usage

[KallynGowdy]

Description

Adds support for listing and displaying registration invite links generated by the bot, showing their status (unused, pending, used, expired, revoked) and usage details.

Changes:

1. Backend API integration (registration-bot.ts):

   • Added types and parsing for the bot's /api/invites endpoint (PR Support jumping to events in notifications and inbox links #48)
   • New RegistrationInvite type with token hash, status, client ID, timestamps, and registration details
   • requestRegistrationInvites() function to fetch invites for the current user (or another user for admins)
   • Robust parsing that drops malformed entries while keeping valid ones

2. UI components (InviteFlow.tsx):

   • New InviteList component displaying invites newest-first with status badges
   • Shows invite issuance date, status (color-coded), client, and token hash
   • Displays summary count ("3 invites · 1 used") above the list
   • Auto-refreshes list when a new link is generated
   • Sticky action buttons that stay visible while scrolling the invite list

3. Styling (InviteFlow.css.ts):

   • New styles for invite list, cards, badges, and detail text
   • Color-coded badge tones: positive (used), neutral (unused/pending), muted (expired/revoked)

4. Helper utilities (inviteList.ts):

   • describeInvite() — formats invite status with human-readable labels and details
   • summarizeInvites() — generates summary text like "2 invites · 1 used"
   • Handles all status types with appropriate tone and detail messaging

5. React hook (useRegistrationInvites.ts):

   • useRegistrationInvites() hook that loads invites on mount and provides a refresh() callback
   • Keeps last-known list on screen while loading new data

6. Tests:

   • Added inviteList.test.ts covering describeInvite() and summarizeInvites() with all status types
   • Added registration-bot.test.ts tests for URL building, response parsing, and HTTP request handling

Fixes the registration flow to show users the history and status of invitation links they've created.

Checklist:

• I have read and understood the Contribution policy.

https://claude.ai/code/session_018uEeWQpUstXyDM2hVAD2X8