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/bot/dispatch.go

@@ -31,9 +31,11 @@ func (r *Registry) Init() error {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 	for _, p := range r.plugins {
+		slog.Info("initializing plugin", "name", p.Name())
 		if err := p.Init(); err != nil {
 			return err
 		}
+		slog.Info("initialized plugin", "name", p.Name())
 	}
 	return nil
 }
@@ -43,12 +45,27 @@ func (r *Registry) DispatchMessage(ctx plugin.MessageContext) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 	for _, p := range r.plugins {
-		if err := p.OnMessage(ctx); err != nil {
-			slog.Error("plugin message handler error",
+		r.safeOnMessage(p, ctx)
+	}
+}
+
+func (r *Registry) safeOnMessage(p plugin.Plugin, ctx plugin.MessageContext) {
+	defer func() {
+		if rec := recover(); rec != nil {
+			slog.Error("plugin message handler panic",
 				"plugin", p.Name(),
-				"err", err,
+				"panic", rec,
+				"sender", ctx.Sender,
+				"room", ctx.RoomID,
+				"body", truncate(ctx.Body, 100),
 			)
 		}
+	}()
+	if err := p.OnMessage(ctx); err != nil {
+		slog.Error("plugin message handler error",
+			"plugin", p.Name(),
+			"err", err,
+		)
 	}
 }
 
@@ -57,12 +74,27 @@ func (r *Registry) DispatchReaction(ctx plugin.ReactionContext) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 	for _, p := range r.plugins {
-		if err := p.OnReaction(ctx); err != nil {
-			slog.Error("plugin reaction handler error",
+		r.safeOnReaction(p, ctx)
+	}
+}
+
+func (r *Registry) safeOnReaction(p plugin.Plugin, ctx plugin.ReactionContext) {
+	defer func() {
+		if rec := recover(); rec != nil {
+			slog.Error("plugin reaction handler panic",
 				"plugin", p.Name(),
-				"err", err,
+				"panic", rec,
+				"sender", ctx.Sender,
+				"room", ctx.RoomID,
+				"emoji", ctx.Emoji,
 			)
 		}
+	}()
+	if err := p.OnReaction(ctx); err != nil {
+		slog.Error("plugin reaction handler error",
+			"plugin", p.Name(),
+			"err", err,
+		)
 	}
 }
 
@@ -77,6 +109,13 @@ func (r *Registry) GetCommands() []plugin.CommandDef {
 	return cmds
 }
 
+func truncate(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n] + "…"
+}
+
 // GetPlugin returns a plugin by name.
 func (r *Registry) GetPlugin(name string) plugin.Plugin {
 	r.mu.RLock()