Add forex plugin, stability fixes, and async HTTP dispatch

- Add forex plugin (Frankfurter v2 API) with rate lookups, analysis,
  DM-based alerts, and daily cron poll. Backfills 1 year of history
  on startup for moving averages and buy signal scoring.

- Fix bot hang caused by SQLite lock contention in reminder polling:
  rows cursor was held open while writing to the same DB. Collect
  results first, close cursor, then process. Same fix in milkcarton.

- Add sync retry loop so the bot reconnects after network drops
  instead of silently exiting. StopSync() for clean Ctrl+C shutdown.

- Add panic recovery to all dispatch, syncer, and cron paths.

- Make all HTTP-calling plugin commands async (goroutines) so a slow
  or dead external API cannot block the message dispatch pipeline.
  Affects: lookup, stocks, forex, anime, movies, concerts, gaming,
  retro, wotd, urls, howami.

- Extract DisplayName to Base, add db.Exec helper, convert silent
  error discards across the codebase.

- Fix UNO mercy-kill bug (eliminated bot continues playing), adventure
  DM nag spam, stats column mismatch, per-call regex/replacer allocs.

- Update README: forex commands, Finance section, 47 plugins.

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

internal/plugin/adventure_scheduler.go

@@ -266,16 +266,17 @@ func (p *AdventurePlugin) midnightReset() {
 				_ = saveAdvCharacter(&char)
 			}
 		} else {
-			// Update streak
-			if char.LastActionDate == time.Now().UTC().Add(-24*time.Hour).Format("2006-01-02") {
+			// Update streak — LastActionDate was set at action time
+			yesterday := time.Now().UTC().Add(-24 * time.Hour).Format("2006-01-02")
+			if char.LastActionDate == yesterday || char.LastActionDate == today {
 				char.CurrentStreak++
-			} else if char.LastActionDate != today {
+			} else {
+				// Gap in activity — start fresh
 				char.CurrentStreak = 1
 			}
 			if char.CurrentStreak > char.BestStreak {
 				char.BestStreak = char.CurrentStreak
 			}
-			char.LastActionDate = today
 			_ = saveAdvCharacter(&char)
 		}
 	}
@@ -293,6 +294,12 @@ func (p *AdventurePlugin) midnightReset() {
 	// Clear flavor history to prevent unbounded memory growth.
 	// Entries are only used for dedup within a day, so clearing at midnight is fine.
 	advClearFlavorHistory()
+
+	// Clear DM reminder dedup — entries are date-keyed so stale after midnight.
+	p.dmRemindedDate.Range(func(key, _ any) bool {
+		p.dmRemindedDate.Delete(key)
+		return true
+	})
 }
 
 // ── Helper ───────────────────────────────────────────────────────────────────