Add markov, emojiboard, achievements, miniflux plugins and adventure catch-up fix

New plugins: encrypted Markov chain generation (9 commands), emojiboard
reaction stats (5 views), Miniflux RSS feed integration (8 commands),
and 48 new achievements across 9 categories. Adventure startup now
unconditionally resets daily actions and respawns expired deaths to
handle missed resets from SQLite contention. README updated with all
new features.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/db/db.go

@@ -966,6 +966,23 @@ CREATE TABLE IF NOT EXISTS forex_alerts (
 	PRIMARY KEY (user_id, currency, threshold)
 );
 
+-- Miniflux RSS
+CREATE TABLE IF NOT EXISTS miniflux_subscriptions (
+	id          INTEGER PRIMARY KEY AUTOINCREMENT,
+	feed_id     INTEGER NOT NULL,
+	room_id     TEXT NOT NULL,
+	paused      INTEGER NOT NULL DEFAULT 0,
+	created_at  INTEGER NOT NULL,
+	UNIQUE(feed_id, room_id)
+);
+
+CREATE TABLE IF NOT EXISTS miniflux_seen (
+	feed_id     INTEGER NOT NULL,
+	entry_id    INTEGER NOT NULL,
+	seen_at     INTEGER NOT NULL,
+	PRIMARY KEY (feed_id, entry_id)
+);
+
 `
 
 // SeedSchedulerDefaults inserts default scheduler jobs if they don't exist.