chore: drop CF→AWS migration tooling and stale JS-port references

The CF→AWS data migration (closed 2026-05-16) is long done and the
tooling isn't wired into any production path. Remove the one-shot binary,
its support package, and the migration runbook.

In live code, replace 'JS-parity' / 'same shape as JS' / 'cross-runtime
KV migration' comments with the real, stable reason for each behavior
(wire-format invariant, null-vs-zero distinction, CloudWatch alarm field
name, etc.). 24 files touched across lolschedule, loldle, wordle, twentyq,
trading, misc, util, server, metrics, ai, keylock.

- delete cmd/migrate_cf_data/
- delete internal/migration/
- delete docs/cf-to-aws-migration-runbook.md

internal/modules/util/chathelper/chathelper.go

@@ -15,14 +15,11 @@ import (
 	"github.com/go-telegram/bot/models"
 )
 
-// SubjectFor mirrors JS getSubject: group/supergroup → chat ID (shared game
-// state), otherwise → user ID. Returns "" when no usable id is present
-// (caller should reply with a "cannot identify chat" error). Channels and
-// unknown chat types fall through to From.ID.
-//
-// Canonical shape: the wordle module previously had an explicit
-// ChatTypePrivate branch returning From.ID, which is identical to the
-// default branch — folded together here.
+// SubjectFor returns the identity key per-module state should be scoped by:
+// group/supergroup → chat ID (shared game state), otherwise → user ID.
+// Returns "" when no usable id is present (caller should reply with a
+// "cannot identify chat" error). Channels and unknown chat types fall
+// through to From.ID.
 func SubjectFor(msg *models.Message) string {
 	if msg == nil {
 		return ""
@@ -39,7 +36,7 @@ func SubjectFor(msg *models.Message) string {
 }
 
 // ArgAfterCommand returns everything after the first space in text, trimmed.
-// Works for `/cmd arg`, `/cmd@bot arg`, etc. JS-parity.
+// Works for `/cmd arg`, `/cmd@bot arg`, etc.
 func ArgAfterCommand(text string) string {
 	if text == "" {
 		return ""
@@ -88,9 +85,9 @@ func ReplyHTML(ctx context.Context, b *bot.Bot, msg *models.Message, text string
 }
 
 // WinRate computes wins/played as a percentage rounded to nearest int.
-// math.Round matches JS Math.round (round half away from zero for positive
-// inputs); plain int(...) truncation would render 2/3 as 66% where JS shows
-// 67%. Returns 0 when played == 0 (avoids NaN).
+// Uses math.Round (round half away from zero for positive inputs) so 2/3
+// renders as 67%, not 66% as plain int(...) truncation would give.
+// Returns 0 when played == 0 (avoids NaN).
 func WinRate(wins, played int) int {
 	if played <= 0 {
 		return 0

internal/modules/util/info.go

@@ -32,7 +32,7 @@ func infoCommand() modules.Command {
 			}
 			chatID := fmt.Sprintf("%d", msg.Chat.ID)
 			// Telegram omits message_thread_id outside forum topics, so a 0
-			// here is "no thread", same as JS's `?? "n/a"`.
+			// here means "no thread" — render as "n/a" instead of "0".
 			threadID := "n/a"
 			if msg.MessageThreadID != 0 {
 				threadID = fmt.Sprintf("%d", msg.MessageThreadID)

internal/modules/util/stickerid.go

@@ -57,8 +57,7 @@ func stickerIDCommand() modules.Command {
 	}
 }
 
-// stickerFrom pulls the sticker out of the *replied-to* message, mirroring the
-// JS handler: ctx.message.reply_to_message.sticker.
+// stickerFrom pulls the sticker out of the *replied-to* message.
 func stickerFrom(msg *models.Message) *models.Sticker {
 	if msg.ReplyToMessage == nil {
 		return nil