[Bug] Windows: sessions imported by kimi migrate invisible in /sessions picker (workDir slash mismatch)

Environment

• kimi-code 0.38.0, native Windows install (~/.kimi-code/bin/kimi.exe)
• Windows, migrated from legacy Python kimi-cli via kimi migrate (chose Config + sessions)

What happened

kimi migrate completed successfully and reported 60+ sessions imported. However, opening /sessions (or kimi --session) inside the same working directory shows none of the imported sessions — only sessions newly created by the native build appear.

Root cause (from local data inspection)

The sessions themselves are imported correctly:

• They exist under ~/.kimi-code/sessions/<workDirKey>/, tagged custom.imported_from_kimi_cli: true
• They are listed in ~/.kimi-code/session_index.jsonl
• They are visible in kimi vis

The problem is a path normalization mismatch in session_index.jsonl:

• Imported entries keep the legacy backslash form: "workDir": "D:\code\edcbook"
• Native 0.38.0 sessions are recorded with forward slashes: "workDir": "D:/code/edcbook"

The session picker appears to filter index entries by exact string match against the current process working directory, so imported entries never match. Historical spelling variants (d:\code\edcbook, d:/code/edcbook, different drive-letter casing) also fragment one real directory into multiple invisible buckets. In my index the same physical directory existed under 4 different spellings.

Expected behavior

• kimi migrate should normalize workDir to the native canonical form when importing, and/or
• the session picker should canonicalize both sides before comparing (on Windows: slash-direction agnostic, drive-letter case-insensitive).

Reproduction

1. On Windows, have legacy kimi-cli sessions created with a backslash cwd (e.g. D:\foo).
2. Install kimi-code 0.38.0, run kimi migrate, choose "Config + N sessions".
3. cd D:\foo && kimi, then /sessions → imported sessions are missing.
4. kimi vis shows them; session_index.jsonl shows their workDir with backslashes.

Workaround

Manually rewriting workDir values in session_index.jsonl to the forward-slash form (D:/foo) makes the imported sessions appear in the picker. No session files needed to be moved.

Happy to provide a debug ZIP or the before/after index files if useful.

Start by tracing kimi migrate's handling of session_index.jsonl and the /sessions picker lookup, using the reported workDir mismatch as the reproduction. Verify the behavior with legacy Windows paths and confirm that imported sessions appear in /sessions without manually editing the index.