fix: escape CSS selector keys to handle special characters

[Slone123c]

Use CSS.escape() for data-key attribute selectors in querySelector to properly handle file paths with non-ASCII characters (e.g., Chinese) and special URL protocols (file://).

What does this PR do?

The desktop app crashes with:
SyntaxError: 'data-key="file://xxxxxx.md""' is not a valid selector.

This occurs because querySelector requires special characters in attribute selectors to be escaped.

Solution

Wrap key values with CSS.escape() before using them in selectors:

// Before
querySelector(`[data-key="${key}"]`)
// After  
querySelector(`[data-key="${CSS.escape(key)}"]`)
Changes
- packages/ui/src/components/list.tsx: Added CSS.escape() to both querySelector calls (lines 72, 84)

### How did you verify your code works?
I did a local test.
1. CSS.escape() correctly escapes :, /, and . characters that are special in CSS selectors
2. The escaped selector successfully finds the element

[github-actions]

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1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

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[github-actions]

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