Web docs: introduce V1 sandbox docs; move legacy runtime/API to Web V0

[enyst]

HUMAN: This PR proposes a first update for OpenHands-Web docs, to address the confusion in the community:

• rename Web -> Web (V0) tab
• move V0 runtimes -> Web (V0) runtimes
• move V0 API -> API (V0)
• create sandbox pages under Web tab
• create a placeholder overview page for V1 API under Web tab

I have checked the mintlify deployment for the new and moved pages.

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Summary

• Add a new Web_V0 tab to keep legacy V0 web documentation out of the primary Web tab.
• Move and rename legacy V0 docs:
  • openhands/usage/runtimes/* → openhands/usage/v0/runtimes/V0_*
  • openhands/usage/advanced/configuration-options → openhands/usage/v0/advanced/V0_configuration-options
  • openapi/openapi.json → openapi/V0_openapi.json
• Add new V1 pages with normal names:
  • openhands/usage/sandboxes/* (Docker / Process / Remote)
  • openhands/usage/api/v1 (V1 API overview)
  • new V1-focused openhands/usage/advanced/configuration-options
• Update navigation + redirects so old /openhands/usage/runtimes/* URLs land on the V1 sandbox docs (or the V0 pages for third-party runtimes).

Why

OpenHands V1 uses sandboxes (including a local process option) rather than the legacy “runtime” terminology. The previous docs prominently surfaced V0 runtime and V0 API material, which is confusing for users.

Notes / Follow-ups

• The V1 sandbox docs are intentionally concise; we can expand with more concrete configuration examples once we align on the supported knobs for Process/Remote selection in the launcher/UI.
• Legacy REST API OpenAPI remains available under Web_V0.

Tests

• python -m json.tool docs.json
• python -m pytest -q

@enyst can click here to continue refining the PR

[openhands-ai]

Looks like there are a few issues preventing this PR from being merged!

• GitHub Actions are failing:
  • .github/workflows/sync-agent-sdk-openapi.yml
  • .github/workflows/sync-docs-code-blocks.yml

If you'd like me to help, just leave a comment, like

@OpenHands please fix the failing actions on PR #275 at branch `docs-v1-web-and-v0-legacy`

Feel free to include any additional details that might help me get this PR into a better state.

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