[BUG] Windows: nested CLAUDE.md is not loaded when a Read path uses an uppercase drive letter (`C:\` vs `c:\`)

Environment: Claude Code VS Code extension 2.1.285, Windows 11. The workspace was opened as c:\Repos\<project>.

What happens: a subdirectory CLAUDE.md is attached (a nested_memory attachment after a Read result) only when the Read tool's file_path starts with a lowercase drive letter. The model often writes absolute paths as C:\…, and then nothing loads.

Evidence from 40 main-session and 60 subagent transcripts in one project, counting Reads of files in a subdirectory that has a CLAUDE.md:

• c:\… paths: 132 loaded it. The 27 that didn't were in transcripts that had already opened that same CLAUDE.md explicitly, which looks like correct handling of files already read.
• C:\… paths: 0 of 67 loaded it.
• The clearest case is one session: the main thread read C:\…\service\src\read\allocation.ts and got no attachment. Its subagent read c:\…\service\src\read\allocation.ts and got service\CLAUDE.md attached immediately.

Expected: Windows paths compare case-insensitively, so C:\ and c:\ should both trigger the load. The comparison probably needs to normalise the drive letter, or the whole path, before matching against the cwd.

Impact: sessions edited directories whose CLAUDE.md rules were never in context.

Related: #2571 (closed), #95104.

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