[BUG] .sql syntax highlighting never renders in Desktop file previewer (Windows)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The file previewer in Claude Desktop does not sustain syntax highlighting for .sql files. Files open in plain black/white text; on the first .sql opened in a session there was a brief flicker (color appears momentarily, then falls back to plain), but on subsequent opens within the same session there is no flicker at all — straight to plain text.

Tested 4 minimal probe files to isolate the variable — all failed identically (no color):

• Bare SELECT 1;, ASCII, 1 line, no comments.
• Same, with a / ... / block comment header prepended.
• SELECT 1; with a -- line comment containing accented characters (á, ó, —, ·).
• 200 lines of SELECT 1; -- line N, pure ASCII.

Also tested both opening mechanisms (chat markdown link vs. sidebar file-tree click) — same result both ways.

Control: a .json file in the same session/previewer renders syntax coloring correctly. This isolates the bug to the sql language grammar specifically, not to file content, size, encoding, or the opening mechanism.

Possibly related: #66440 — "Syntax Highlighting of C# disappears after a brief moment" (macOS, .cs files, area:desktop/area:ui, open/unresolved). Same class of symptom (color flickers then falls back to plain) and same component (Desktop file previewer), but for C# on macOS rather than SQL on Windows.

What Should Happen?

.sql files should retain syntax highlighting the same way .json (and presumably other supported languages) do.

Error Messages/Logs

Steps to Reproduce

1. Open Claude Desktop on Windows.
2. Create/open any .sql file via the file tree sidebar, or via a markdown link from chat.
3. Observe the previewer: no sustained syntax coloring (SQL keywords, strings, comments all render as plain text) — brief flicker on the first file opened in the session, none on subsequent opens.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Latest (Claude Desktop, exact version not surfaced in UI)

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

Possibly related: #66440 — "Syntax Highlighting of C# disappears after a brief moment" (macOS, .cs files, area:desktop/area:ui, open/unresolved). Same class of symptom (color flickers then falls back to plain) and same component (Desktop file previewer), but for C# on macOS rather than SQL on Windows.