[Bug] Desktop app session index not updated when .jsonl files restored to disk

Bug Description
Title: [BUG] Desktop: deleting a session removes it from the app's index permanently — restoring the .jsonl to ~/.claude/projects/ is not picked up by desktop (but CLI --resume reads it fine)
What's wrong: After deleting a session via the sidebar menu, copying its .jsonl back into the project directory does not make it reappear in the desktop app. The CLI resumes the same file without issue, which suggests desktop relies on an internal index rather than scanning the directory, with no rescan/reimport path.
Impact: Beyond the hang itself, the downtime consumed part of an active 5-hour usage window — the app being unusable doesn't pause the clock, so the bug effectively costs paid capacity, not just time.
Expected: Desktop should detect transcripts present on disk (rescan on launch, or an explicit "import session" option).

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.172
• Feedback ID: 864c16e5-ac1b-433f-9436-eeb5a400ae1a

Errors

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