feat(sticker): add sticker pack module

Nine commands mirroring the names @Stickers uses: /newpack, /mypack,
/addsticker, /delsticker, /editsticker, /ordersticker, /setpackicon,
/renamepack and /delpack, plus a confirm callback for the destructive
one. Sources are replied stickers, photos or image documents; photos are
downloaded, resampled to 512px and re-uploaded.

One pack per user, keyed by owner id. Creating a pack is the only
operation here that makes a durable, publicly linkable object on a user's
behalf, so it is built around proving ownership rather than assuming it:

- A name is claimed globally and create-only before Telegram is called.
  A pending record alone proves only that a caller *asked* for a name,
  which is exactly what someone naming a victim's public slug also does.
- Adopting an existing set additionally requires that the claim predates
  this invocation. The claim lives in our store and the pack lives at
  Telegram, so a wiped store would otherwise make every pack adoptable.
- Names are released only on positive evidence that no pack stands behind
  them, never on a generic failure, so a transient error cannot hand a
  live name to the next caller.
- Ownership refusals are byte-identical across failure modes, so they
  cannot be used to probe which sets exist.

Error classification is positive-only throughout: "the set is gone" and
"nothing was created" are each proven from a specific Telegram response,
never inferred from an error. Post-action commits run on a context
detached from the request so a shutdown mid-handler cannot lose the
record of something Telegram already did.

Enabled explicitly via MODULES rather than by default.

cmd/server/command_menu_test.go

@@ -72,6 +72,15 @@ func TestCommandDiscovery_AllPublicCommandsHaveSafeMetadata(t *testing.T) {
 		"monkeyd_crawl":        "<url> [font_size]",
 		"monkeyd_tags":         "<url>",
 		"random":               "<option,...>",
+		"newpack":              "<pack> <title...>",
+		"mypack":               "",
+		"addsticker":           "[emoji...]",
+		"delsticker":           "",
+		"editsticker":          "<emoji...>",
+		"ordersticker":         "<position>",
+		"setpackicon":          "",
+		"renamepack":           "<title...>",
+		"delpack":              "",
 		"stats":                "[users | user <username> | cmd <command_name>]",
 		"stock_events":         "<ticker> [days]",
 		"stock_info":           "<ticker>",
@@ -91,7 +100,11 @@ func TestCommandDiscovery_AllPublicCommandsHaveSafeMetadata(t *testing.T) {
 	if len(menu) != len(reg.PublicCommands()) {
 		t.Fatalf("menu commands = %d, public commands = %d", len(menu), len(reg.PublicCommands()))
 	}
+	// This map lists the commands whose parameter strings are pinned; commands
+	// absent from it are not asserted (the lookup yields "" for them).
+	seen := map[string]bool{}
 	for _, command := range reg.PublicCommands() {
+		seen[command.Name] = true
 		if got := command.Parameters; got != expectedParameters[command.Name] {
 			t.Errorf("/%s parameters = %q, want %q", command.Name, got, expectedParameters[command.Name])
 		}
@@ -107,6 +120,20 @@ func TestCommandDiscovery_AllPublicCommandsHaveSafeMetadata(t *testing.T) {
 		}
 	}
 
+	// Every expectation must correspond to a registered command.
+	//
+	// Without this, an entry whose command stopped being registered simply
+	// stopped being checked: the forward loop only visits commands that exist,
+	// so removing a whole module from factories() left the suite green. That is
+	// also what makes the parameterless entries above load-bearing rather than
+	// decorative — "" == "" asserts nothing on its own, but the command having
+	// to exist at all does.
+	for name := range expectedParameters {
+		if !seen[name] {
+			t.Errorf("/%s is expected but not registered — a module dropped out of factories()", name)
+		}
+	}
+
 	help := moduleutil.RenderHelp(reg)
 	if utf8.RuneCountInString(help) > telegramMessageMaxRunesForTest {
 		t.Fatalf("/help source is %d characters, exceeds conservative Telegram limit %d", utf8.RuneCountInString(help), telegramMessageMaxRunesForTest)

cmd/server/main.go

@@ -26,6 +26,7 @@ import (
 	"github.com/tiennm99/miti99bot/internal/modules/misc"
 	"github.com/tiennm99/miti99bot/internal/modules/monkeyd"
 	"github.com/tiennm99/miti99bot/internal/modules/stats"
+	"github.com/tiennm99/miti99bot/internal/modules/sticker"
 	"github.com/tiennm99/miti99bot/internal/modules/stock"
 	"github.com/tiennm99/miti99bot/internal/modules/util"
 	"github.com/tiennm99/miti99bot/internal/modules/wordle"
@@ -91,6 +92,7 @@ func factories() map[string]modules.Factory {
 		"gold":               gold.New,
 		stock.CollectionName: stock.New,
 		"stats":              stats.New,
+		"sticker":            sticker.New,
 	}
 }