feat: let the reader switch off daily detection

Guessing from a source's wording is right most of the time, and someone
who finds it wrong often enough should be able to stop it rather than
dismiss the same false positive every patch.

Off, only events the reader marked themselves get a checklist. It
silences the guess rather than deleting anything: overrides, ticks and
streaks all survive, so switching it back on restores exactly what was
there. With it off, marking an event stores an explicit yes, since there
is no longer a detection for an override to agree with.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

src/client/state/usePrefs.ts

@@ -10,6 +10,12 @@ export interface Prefs {
   hiddenGames: GameId[];
   /** How the list is ordered. Deadline order is the default and the fallback. */
   sort: SortMode;
+  /**
+   * Whether to guess which events repeat daily from what the source printed.
+   * Off leaves only the ones the reader marked themselves; it never discards a
+   * mark or a logged day, so it is reversible.
+   */
+  detectDaily: boolean;
   showCompleted: boolean;
   /** Reveal events the reader has ignored, so they can be restored. */
   showIgnored: boolean;
@@ -24,6 +30,7 @@ function defaults(): Prefs {
     region: guessRegion(),
     hiddenGames: [],
     sort: "ending",
+    detectDaily: true,
     showCompleted: true,
     showIgnored: false,
     regionConfirmed: false,