[gitKashish]

Summary

Closes #65528

Previewing two files with the same name (e.g. docs/README.md and guide/README.md) showed two tabs both titled Preview README.md, with no way to tell them apart.

Panes disambiguate tabs by calling Item::tab_content_text with an increasing detail until the titles differ, then pass the chosen level to tab_content. MarkdownPreviewView::tab_content_text ignored detail, so the pane never got past level 0.

• tab_content_text now asks the source editor for its title at the requested detail and prefixes Preview . Without a name clash it's unchanged (Preview README.md).
• tab_content shows the parent directories after the title as a small muted label, like editor tabs. For that, the description logic in Editor::tab_content moved into a new public Editor::tab_description, which both use, so editor tabs render exactly as before.
• In the tab switcher (truncate_title_middle), the preview row now shrinks and truncates the same way editor entries do.

The preview still doesn't report a project path, so navigation history and reopening closed tabs are unaffected.

Testing

• Added preview_tabs_for_files_with_the_same_name_show_their_directory, which previews docs/README.md and guide/README.md in one pane, runs the pane's disambiguation (workspace::tab_details) and checks the titles are Preview docs/README.md and Preview guide/README.md (using path! so it works on Windows). It fails without the fix.
• Manually tested on Linux: two previews of README.md from different directories show docs / zed after the title, matching the editor tabs; the tab switcher entries truncate like editor entries.

Self-review

• I've reviewed my diff for quality, security, reliability, and performance.
• UI changes follow the checklist.
• Tests cover the new or changed behavior.

Release Notes:

• Fixed Markdown preview tabs for files with the same name not showing their directory.

[SomeoneToIgnore]

Thank you, a few notes.

[SomeoneToIgnore]

Editor::tab_content_text(0) can return a full path for single-file worktrees with an empty relative path (items.rs:2336–2343).
For an external /tmp/out/README.md, the new code supplies Preview /tmp/out/README.md as the primary label and /tmp/out again as the subtitle, without any collision.

Keep the path-aware key for disambiguation, but build the displayed label from editor.title(cx), matching the existing editor rendering.

[gitKashish]

Good catch, thanks! Fixed, the title now uses editor.title(cx). MB I didn't consider external files.

[SomeoneToIgnore]

Great, thank you for the context on the new API.

One more findings meanwhile.

[SomeoneToIgnore]

Nice, thank you for all the fixes!

[gitKashish]

Thanks for the thorough review, learned a lot from it!