feat(backtotitle): narrow the daily-04:00 suppress to the actual caller

[tkgstrator]

`Hook_BackToTitleSuppress.m` is in the tree but `InstallBackToTitleSuppressHook` is commented out in `Tweak.m` because the naive approach (replacing `BackToTitleSequence.RunAsync` with a no-op UniTask) was too broad — it also killed user-initiated back-to-title and `KEBNavigateToTitleScene` (Account Switch).

Goal

Suppress only the 04:00 JST daily-reset transition, leaving every other call to `BackToTitleSequence.RunAsync` intact.

Investigation steps

1. Run the JB install across midnight and grep the in-sandbox log for `[BACK2TITLE]` lines (the observer hook on `BackToTitleSequence.d__0.MoveNext` is already installed).
2. Walk back from the log timestamp in `dump.cs` to find the call site that fired `RunAsync` at 04:00 — likely something around `MenuScene.OnActivateAsync`'s date-change branch, `HomePage.OnEnterAsync`, or a notification stream handler.
3. Replace the broad `RunAsync` site patch with a targeted hook at that caller (probably `CAVE_ENTRY` to skip the `RunAsync` call entirely, or an inline patch if the conditional itself is small).

Acceptance

• 04:00 boundary on JB no longer evicts the user to the title.
• Account Switch (`KEBNavigateToTitleScene`) and manual title-button taps still work.
• Once stable on JB, port the same patch shape to chinlan via the recipe.

Related

• PR feat(chinlan): add entry-cave kind so Force Register works on chinlan too #16 — entry-cave kind that this feature would build on.
• PR feat(chinlan): port account switch + Accept Seat to entry caves, document cave kinds #17 — current state of CAVE_OBSERVER / CAVE_ENTRY wiring (the BackToTitle suppress remains commented out there too).