#20986: fix(docs): remove dead link to non-existent formal-models repo

## Summary Removes dead links to `vignesh07/openclaw-formal-models` (returns 404) in the formal verification docs. Replaces with a note that the repo is not yet publicly available. ## Problem The formal verification docs reference a GitHub repo that does not exist: - `https://github.com/vignesh07/openclaw-formal-models` → **404** This affects both the English and Chinese documentation pages. ## Fix - Replaced the dead link text with a note + reference to this issue - Updated the `git clone` command in the code block to a commented placeholder - Fixed in both `docs/security/formal-verification.md` and `docs/zh-CN/security/formal-verification.md` **2 files changed** Fixes #20871 ## Local Validation - Verified both files render correctly - Confirmed no other references to the dead URL exist in the codebase ## Scope Docs-only change. Zero code impact. ## AI Assistance Claude Code assisted with searching the codebase for all references and updating both language versions. ## Author **Miloud Belarebia** — [@miloudbelarebia](https://github.com/miloudbelarebia) <!-- greptile_comment --> <h3>Greptile Summary</h3> Removes dead link to non-existent `vignesh07/openclaw-formal-models` repository (404) from formal verification docs. Replaces with note that repo is not yet publicly available, referencing issue [#20871](https://github.com/openclaw/openclaw/issues/20871). - Updated both English (`docs/security/formal-verification.md`) and Chinese (`docs/zh-CN/security/formal-verification.md`) documentation - Converted `git clone` command to commented placeholder with updated organization path (`openclaw/openclaw-formal-models`) - Verified no other references to the dead URL exist in codebase <h3>Confidence Score: 5/5</h3> - This PR is completely safe to merge with zero risk - Documentation-only change that fixes a broken link with no code impact. Changes are straightforward, properly localized, and verified to be complete across the codebase. - No files require special attention _{Last reviewed commit: 668ceca} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->