docs: generate Holodex Next v3 missing features issue

[sphinxrave]

Generated a markdown file (issue.md) that documents missing routes, pages, component disparities, bugs, and TODOs in the new React implementation compared to the v2 Vue implementation. This covers multiview, video player styling, TLDex features, tabs, user services, and navigation.

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PR created automatically by Jules for task 4816587985760765056 started by @sphinxrave

[google-labs-jules]

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