fix(editor): single-letter tags in select/multi-select table cell (#14808)

### Summary of Changes
Resolves #14715 and #14280.

When a user types into a **Select/Multi-Select** table cell to
create/choose a tag, that character is stashed on the cell container
(setTagDraft) instead of going through valueSetFromString. Opening the
tag picker reads it via consumeTagDraftFromTableCellHost.

### Verification
- Added unit test to check that single-character input doesn't
immediately call valueSetFromString.



https://github.com/user-attachments/assets/432b2693-52f9-4ab4-a694-8440aea007a3



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Tag selection popups now initialize with draft text from keypresses in
tag columns, improving user experience when editing tags.

* **Tests**
* Added comprehensive hotkey tests for single-select and multi-select
tag column behavior.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->