Improved CSS styles for HTML export

This release contains the following enhancements:

1) HTML export now includes default styles for Docutils output, based on
Docutils' html4css1.css. RST options such as :align: center on
images and figures now take effect.

2) Fixed: table headers in HTML export no longer break words in the
middle. Header text wraps only at natural break points, so a column no
longer shrinks to one or two characters wide.

3) Fixed: when several error messages appear at once, the notification
toast now stacks them in a column, so each message stays readable.

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What's Changed

• chore: update technical writing guide skill to v1.1 by @stanislaw in #3216
• Fix table header and toast layouts by @mettta in #3221
• feat(export/html): add default CSS for Docutils (from html4css1.css) by @mettta in #3228
• chore: bump github/codeql-action from 4.37.9 to 4.38.1 in the github-actions group across 1 directory by @dependabot[bot] in #3220
• release: bump version to 0.30.2 by @stanislaw in #3231

Full Changelog: 0.30.1...0.30.2