design-gate: retain unsupported Windows verbatim namespaces

[TreyThomasCodes]

Design gate

Track the Windows verbatim-path namespace policy implemented in PR #302:
#302

Only valid DOS-drive and UNC extended-length paths may lose their verbatim prefix. Unsupported or malformed namespaces, including \\?\Volume{GUID}\, must retain that prefix rather than being reinterpreted as DOS paths.

The PR consolidates the Rust conversion paths and aligns the TypeScript project-root identity normalizer with this policy.

[aft-alfonso]

Design approved and labelled. Keeping the verbatim prefix on anything that is not a valid DOS-drive or UNC extended-length path is the right policy - a \\?\Volume{GUID}\ spelling has no DOS form, and the earlier per-site strippers manufactured one. Consolidating the three private copies (inspect normalization, oxc resolver, LSP URI rendering) and the batch-shim converter onto one strict windows_path module, with the TypeScript root-identity normalizer aligned to the same rule, is what we want. #302 merges once its matrix is green.