* fix: correct bulk session delete endpoint + surface deleted count
- Fix Retrofit @POST path from 'api/sessions/delete' to 'api/sessions/bulk-delete'
- Change response type from Response<Unit> to Response<BulkDeleteResponse>
- Add BulkDeleteResponse model (ok, deleted) matching backend contract
- Surface backend 'deleted' count in toast message instead of using client-side count
Backend contract (web_server.py:10750):
POST /api/sessions/bulk-delete
Body: { "ids": [...], "delete_all": false }
Response: { "ok": true, "deleted": <count> }
Fixes#651
* fix: replace client-side session list filter with full refresh after bulk delete
- Call loadSessions() + loadStats() after successful bulk delete instead of
filtering sessions/searchResults locally via 'ids' — fixes state desync
when backend deletes fewer sessions than requested (partial success) and
is correct for delete_all=true where ids may be empty
- Show 'No sessions were deleted' toast when deletedCount == 0
- Extract toastMsg to separate val to satisfy ktlint lint rules
Addresses review findings: UI state desync, delete_all handling, hardcoded
pluralizing, and zero-deletion UX.
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Co-authored-by: M57 <Hy4ri@users.noreply.github.com>
