Sidebar shows all pre-reinstall sessions under "Other" instead of project group after CLI reinstall

Description
After reinstalling Claude Code (Windows), all sessions created before the reinstall for an existing project are now permanently grouped under "Other" in the sidebar instead of under the project's own group (e.g., "TAMKIN"). New/resumed sessions after reinstall don't merge into the original project group either.

Environment

• OS: Windows 11 Home 10.0.26200
• Install method: native Windows installer (binary at %USERPROFILE%\.local\bin\claude.exe)

Steps to reproduce

1. Have an existing project with many prior sessions (58 in this case), correctly grouped under a project name in the sidebar.
2. Reinstall Claude Code (native Windows installer).
3. Resume an old session via claude --resume from the project directory.
4. Observe: the session now appears under "Other" in the sidebar, not under the original project group.

What I checked

• Local session transcripts (~/.claude/projects/<encoded-path>/*.jsonl) are fully intact - no data loss.
• ~/.claude.json had two separate projects entries for the same folder: one keyed with backslashes (D:\..., original) and one with forward slashes (D:/..., created after reinstall). Merging them into one entry had no effect on the sidebar grouping.
• The sidebar's "Move to group" context-menu option only offers creating a new custom group - no way to manually reassign a session to its original project group.
• Suspect a machineID change on reinstall may be the real cause, if session-to-project association is tracked server-side by device identity rather than local path alone.

Additional (possibly related) issue
The reinstall also didn't add %USERPROFILE%\.local\bin (where claude.exe lives) to the user PATH, so claude was "not recognized" in any existing terminal until added manually.

Impact
Cosmetic/organizational only - all data remains fully accessible via claude --resume. But grouping never self-corrects for pre-existing sessions after a reinstall.