Truncate long filenames in file browser

[bendichter]

Summary

• Fixes UI: rendering of long filenames on the asset navigation window #2725
• Moves filename text from the #prepend slot (which has no width constraints) into a v-list-item-title element, which has built-in CSS for text-overflow: ellipsis + overflow: hidden + white-space: nowrap
• Adds a title attribute so the full filename is visible on hover

Before

Test plan

• Navigate to a dandiset with long filenames (e.g. dandiset 000409, sub-CSH-ZAD-001)
• Verify long filenames truncate with ellipsis instead of overflowing
• Verify full filename appears on hover tooltip
• Verify folder names and ".." navigation still work correctly

🤖 Generated with Claude Code

[bendichter]

After:

[yarikoptic]

@waxlamp @jjnesbitt inviting you to review!

[yarikoptic]

@bendichter "you" specified Test plan with 4 items none of which is marked out. Can you carry out testing there? could/should we incorporate that within our e2e tests somehow?

[bendichter]

To be clear: I have done this, though since we do not have automatic previews for PRs, it's hard for me to link to a specific page that demonstrates this. A reviewer should get this to run locally and confirm all of these points independently.

[yarikoptic]

To be clear: I have done this, though since we do not have automatic previews for PRs,

? do you know of any on sandbox with the long ones? link is like

https://deploy-preview-2726--sandbox-dandiarchive-org.netlify.app/dandiset/200560/draft/files?location=sub-YAML-Subject-Name&page=1