Allow Customizable Sub-Day Intervals for the Skip Button

The current functionality of the Skip button in RemNote defaults to a 1-hour interval, which results in skipped cards leaving the active study queue. This is limiting, as users may want to tackle harder cards more intensively without losing them from short-term focus.

I propose allowing users to customize the interval for the Skip button to any duration, such as seconds, minutes, or hours (e.g., 5 minutes). This would bring RemNote closer to how Anki handles card intervals, where cards marked as "Again" or "Hard" return to the deck within sub-day intervals (e.g., <1 minute or <6 minutes). By customizing the Skip interval, users can prioritize reviewing easier cards quickly while delaying harder ones for a few minutes, maintaining their flow and improving retention.

In practice, after marking certain flashcards as "Forgot" (default: 1 minute) and others as "Skipped" (customized, e.g., 5 minutes), the program should prioritize showing the "Forgot" cards until they’re either recalled or marked as "Skipped," "Partially Recalled," etc. Once the custom interval elapses, the previously skipped cards should re-enter the queue. This system would allow users to focus on intensive bursts of memorization, improving short-term recall while ensuring harder cards aren't sidelined for too long.

This customizable interval for the Skip button would greatly enhance the flexibility and efficiency of learning sessions, especially for intensive study periods.