GHSA-8vm4-g489-v3w7

### Summary User-controlled content in comments and rich text cells was rendered via `v-html` without sanitization, enabling stored XSS.

### Details Comments in `Comments.vue` and rich text in `TextArea.vue` were parsed by markdown-it with `html: true` and injected via `v-html`. The codebase had `vue-dompurify-html` available but these paths used raw `v-html`. Server-side, `Comment.insert()` used `extractProps()` instead of `extractPropsAndSanitize()`.

Commenter role is sufficient for the comments vector; Editor role for rich text.

This issue was independently reported; see also GHSA-rcph-x7mj-54mm and GHSA-wwp2-x4rj-j8rm for the same root cause found by GitHub Security Lab.

### Impact Stored XSS — malicious scripts execute for any user viewing the comment or cell.

### Credit This issue was reported by [@bugbunny-research](https://github.com/bugbunny-research) (bugbunny.ai).