Improve UX for date-sharded LongChat archives #27

Summary

Now that solid-chat supports both single-file chats and date-sharded archives (via #26), the UX could be improved to better handle long chat archives.

Current State

• Date navigation works (prev/next day with gap skipping)
• Single day loads at a time
• No visual distinction between "short" and "long" chats

UX Improvements to Consider

1. Visual indicator for archive chats

• Show an archive/calendar icon for date-sharded chats
• Display total date range (e.g., "2020 - 2026")

2. Date picker

• Jump to specific date instead of clicking prev/next repeatedly
• Calendar widget or date input

3. Message count per day

• Show "16 messages" badge on date label
• Help users find active days

4. Infinite scroll / lazy loading

• Load previous day automatically when scrolling to top
• Seamless browsing without clicking buttons

5. Search across days

• Find messages across the entire archive
• Jump to specific day containing match

6. Index file support

• Read index.json at root for metadata
• Display chat title, creation date, participant count

7. "Jump to today" button

• Quick return to most recent messages
• Useful after browsing history

Priority Suggestion

1. Date picker (high value, moderate effort)
2. Jump to today (quick win)
3. Message count badge (quick win)
4. Infinite scroll (higher effort)

Related

• Support date-sharded LongChat archives #25 - Original sharding support issue
• Add date navigation for sharded chat archives #26 - Date navigation PR