docs(connectors): document the Wiz runtime reachability verdict

[svader0]

Description

This PR documents the reachability verdict that the Wiz connector now sends. If the Wiz Runtime Sensor marks a vulnerability finding as "Validated in Runtime", the connector records a Reachable (runtime) verdict. If the flag is false or missing, the connector sends no verdict.

• connectors/toolreference/wiz.md: new "Runtime Reachability" section. It says what the flag means, why a false or missing flag gives no verdict, that Issues never get a verdict, and links to "How verdicts end". It also says that a verdict expires 30 days after Wiz last updates the finding, because the connector syncs only updated findings, and shows how to give the Wiz source a longer window with DD_REACHABILITY_SOURCE_STALENESS_DAYS.
• triage_findings/finding_scoring/reachability.md: a Wiz connector row in the "Sources that report reachability" table.

The meaning of the flag comes from Wiz's public material: the Wiz blog post "Is Wiz a Runtime Security Tool?" and a Wiz on-demand webinar. Both say the sensor checks what is loaded in memory. The Wiz field reference needs a Wiz login, and nobody on this change checked it.

Test results

• npm ci && npm run build in docs/: Hugo finishes with no ERROR lines.
• The new link to /triage_findings/finding_scoring/reachability/#how-verdicts-end matches the heading id in the built page.

Documentation

This PR is the documentation change. It edits the English pages only. The translated pages follow the quarterly refresh in docs/TRANSLATIONS.md.

Checklist

• Make sure to rebase your PR against the very latest dev.
• Submit all PRs, features and bug fixes alike, against the dev branch.
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• Your code is Ruff compliant (no Python change).
• Your code is python 3.13 compliant (no Python change).
• If this is a new feature and not a bug fix, you've included the proper documentation in the docs at https://github.com/DefectDojo/django-DefectDojo/tree/dev/docs as part of this PR.
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• Add applicable tests to the unit tests (docs only).
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