feat: let readers ignore events they don't care about

Ignoring is not completing. "Done" keeps an event visible and counted;
"not interested" removes it from both views, which is the entire point.

Completions and ignores are the same shape and want the same guarantees, so
they now share one mark-set implementation — union merge on import, never a
removal, since nothing else holds a copy. Both ride in the export file.

Ignored events stay recoverable: the count and a reveal toggle appear in
settings once there is something to reveal.

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

src/client/state/storage.ts

@@ -12,6 +12,7 @@ const NS = "gacha-tracker:v1";
 
 export const KEYS = {
   completions: `${NS}:completions`,
+  ignored: `${NS}:ignored`,
   prefs: `${NS}:prefs`,
 } as const;
 

src/client/state/useCompletions.ts

@@ -1,55 +0,0 @@
-import { useCallback, useEffect, useState } from "react";
-import { KEYS, readJson, writeJson } from "./storage.ts";
-
-export interface Completion {
-  completedAt: string;
-}
-export type Completions = Record<string, Completion>;
-
-/**
- * Completion marks, keyed by event ID.
- *
- * Writes are optimistic and local — there is no round trip and no failure case
- * to design for.
- */
-export function useCompletions() {
-  const [completions, setCompletions] = useState<Completions>(() =>
-    readJson<Completions>(KEYS.completions, {}),
-  );
-
-  useEffect(() => {
-    writeJson(KEYS.completions, completions);
-  }, [completions]);
-
-  const toggle = useCallback((id: string) => {
-    setCompletions((prev) => {
-      if (prev[id] !== undefined) {
-        const { [id]: _removed, ...rest } = prev;
-        return rest;
-      }
-      return { ...prev, [id]: { completedAt: new Date().toISOString() } };
-    });
-  }, []);
-
-  /**
-   * Import merges and never removes. A completion present on either side stays
-   * completed — an import that silently wiped marks would be unrecoverable,
-   * since nothing else holds a copy.
-   */
-  const merge = useCallback((incoming: Completions) => {
-    setCompletions((prev) => {
-      const next = { ...prev };
-      for (const [id, value] of Object.entries(incoming)) {
-        const existing = next[id];
-        // Keep the earlier of the two marks; union of IDs, never a removal.
-        next[id] =
-          existing === undefined || value.completedAt < existing.completedAt
-            ? value
-            : existing;
-      }
-      return next;
-    });
-  }, []);
-
-  return { completions, toggle, merge };
-}

src/client/state/usePrefs.ts

@@ -8,6 +8,8 @@ export interface Prefs {
   /** Games the reader has switched off. Stored as hidden so a newly added game shows up by default. */
   hiddenGames: GameId[];
   showCompleted: boolean;
+  /** Reveal events the reader has ignored, so they can be restored. */
+  showIgnored: boolean;
   /** False until the reader confirms or changes the guessed region. */
   regionConfirmed: boolean;
   /** False until the reader has picked their games on first run. */
@@ -19,6 +21,7 @@ function defaults(): Prefs {
     region: guessRegion(),
     hiddenGames: [],
     showCompleted: true,
+    showIgnored: false,
     regionConfirmed: false,
     onboarded: false,
   };