Migrate documentation to Fumadocs and verify MCSS 13.10.0 workflows

[PouletteMC]

The documentation moves to a static Fumadocs/Next.js site with refreshed guides and API reference, then incorporates hands-on verification against a disposable MCSS 13.10.0 Windows installation.

Changes

• Replace the previous documentation stack with MDX navigation, generated v1/v2 API pages, browser-side search, legacy route compatibility, and Bun-based build/hosting workflows.
• Refresh MCSS, Minecraft/Java, networking, and troubleshooting guidance, with sources and verification limits recorded in CONTENT_REVIEW.md.
• Update creation/import, Java, settings, backup/recovery, and remote-management guides; add scheduling and installation relocation guides.
• Add 16 actual application screenshots, linking relevant guide images to full-size assets, plus a dated exploration report and sanitized API request/response evidence.

Validation

• bun run build, bun run typecheck, and bun run check:export passed using Bun 1.3.11.
• Export validation covered 246 HTML pages, 74 API operations, 25 legacy routes, links/assets/bookmarks, and guide/API search.
• Reviewed changed guides at desktop and 390-pixel narrow widths; verified both new guides in search.
• The production build completed with two nonfatal CSS optimizer warnings about ::highlight.

Review notes

Restricted API-key requests returned responses beyond their configured permissions in the disposable test instance, with results varying by request sequence/restart. The guides distinguish intended permissions from observed behavior; the evidence report and sanitized transcripts retain the discrepancies for maintainer investigation. Temporary credentials were revoked and the test instance was stopped. Untested workflows are listed explicitly in the report.

This PR includes the full dev branch migration and exploration changes. Merging into main triggers the existing GitHub Pages publication workflow.

[filliravaz]

Some pages are good. Still, most items need some sort of work.
AI also found this:

Three newly captured 13.10.0 screenshots are stored in public/img/ and documented in contributor notes, but never referenced in any .mdx file:
public/img/docs/getting-started/first-launch-13-10-0.png (could be used in first-server.mdx)
public/img/docs/panel/disabled-panel-13-10-0.png
public/img/docs/panel/remote-access-manager-13-10-0.png
34 older Docusaurus screenshots remain in public/img/ without being referenced anywhere.

No reason to not fix.

This took some time... Hopefully it's useful! :D

[filliravaz]

Some pages are good. Still, most items need some sort of work.
AI also found this:

Three newly captured 13.10.0 screenshots are stored in public/img/ and documented in contributor notes, but never referenced in any .mdx file:
public/img/docs/getting-started/first-launch-13-10-0.png (could be used in first-server.mdx)
public/img/docs/panel/disabled-panel-13-10-0.png
public/img/docs/panel/remote-access-manager-13-10-0.png
34 older Docusaurus screenshots remain in public/img/ without being referenced anywhere.

No reason to not fix.

This took some time... Hopefully it's useful! :D