feat(modules): port util + misc; expose Registry to handlers

Phase 5a of go-port-cloud-run plan: port first 2 of 4 modules (wordle/loldle
deferred to later phase). Port util.go, info.go, help.go, stickerid.go and
misc.go with tests. /help renders registry view; /info exposes chat/thread/
sender ids; /stickerid (private) returns bot-scoped file_ids; /ping writes
last_ping KV ms-epoch JSON for byte-parity, /mstats reads it, /fortytwo is
easter egg.

Registry-pointer-in-Deps required for /help to access module registry—pointer
captured at factory time, stable post-Build. Static factory catalog moved from
modules pkg to cmd/server to break import cycle. Code-review fixes applied in
same session: /info nil-deref guard, KV wire-format parity.

cmd/server/main.go

@@ -12,6 +12,8 @@ import (
 	"time"
 
 	"github.com/tiennm99/miti99bot-go/internal/modules"
+	"github.com/tiennm99/miti99bot-go/internal/modules/misc"
+	"github.com/tiennm99/miti99bot-go/internal/modules/util"
 	"github.com/tiennm99/miti99bot-go/internal/server"
 	"github.com/tiennm99/miti99bot-go/internal/storage"
 	"github.com/tiennm99/miti99bot-go/internal/telegram"
@@ -25,6 +27,16 @@ var secretEnvKeys = []string{
 	"CRON_SHARED_SECRET",
 }
 
+// factories is the static module catalog. Adding a new module is a one-line
+// change here. Lives in main rather than the modules package to avoid an
+// import cycle (modules → util → modules).
+func factories() map[string]modules.Factory {
+	return map[string]modules.Factory{
+		"util": util.New,
+		"misc": misc.New,
+	}
+}
+
 // firestoreInitTimeout caps client construction at startup. Cloud Run cold
 // start budget is 500ms target; firestore.NewClient is normally fast but
 // network blips can make it hang. Fail fast and let Cloud Run restart us.
@@ -53,7 +65,7 @@ func main() {
 		log.Fatalf("telegram bot init: %v", err)
 	}
 
-	reg, err := modules.Build(cfg.Modules, modules.Factories, provider, cfg.ModuleEnv)
+	reg, err := modules.Build(cfg.Modules, factories(), provider, cfg.ModuleEnv)
 	if err != nil {
 		log.Fatalf("module registry: %v", err)
 	}