fix: preserve user napcat.json config across updates (#1765)

* Initial plan

* fix: prevent o3HookMode from being reset to enabled after NapCat updates

Agent-Logs-Url: https://github.com/NapNeko/NapCatQQ/sessions/98ea8e7d-4ee4-43c1-ac33-2714fba480e3

Co-authored-by: sj817 <74231782+sj817@users.noreply.github.com>

* fix: restore o3HookMode default to 1, harden updater against path traversal

Agent-Logs-Url: https://github.com/NapNeko/NapCatQQ/sessions/53b58325-1685-4961-803e-93091dd8b1c4

Co-authored-by: sj817 <74231782+sj817@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: sj817 <74231782+sj817@users.noreply.github.com>