feat(bot): add wizard state for reminder creation

apps/bot/src/telegram/state.ts

@@ -41,3 +41,53 @@ export function consumePendingSendToGroup(userId: number): string | null {
   if (Date.now() >= pending.expiresAt) return null;
   return pending.groupId;
 }
+
+// Reminder creation wizard state.
+export type WizardStep =
+  | "pick_account"
+  | "pick_group"
+  | "compose"
+  | "set_time"
+  | "confirm";
+
+export type WizardState = {
+  step: WizardStep;
+  accountId?: string;
+  groupId?: string;
+  text?: string | null;
+  mediaId?: string | null;
+  caption?: string | null;
+  scheduledAt?: Date;
+  expiresAt: number;
+};
+
+const wizardState = new Map<number, WizardState>();
+const WIZARD_TTL_MS = 30 * 60 * 1000;
+
+export function getWizard(userId: number): WizardState | null {
+  const w = wizardState.get(userId);
+  if (!w) return null;
+  if (Date.now() >= w.expiresAt) {
+    wizardState.delete(userId);
+    return null;
+  }
+  return w;
+}
+
+export function startWizard(userId: number): WizardState {
+  const w: WizardState = { step: "pick_account", expiresAt: Date.now() + WIZARD_TTL_MS };
+  wizardState.set(userId, w);
+  return w;
+}
+
+export function updateWizard(userId: number, patch: Partial<WizardState>): WizardState | null {
+  const w = getWizard(userId);
+  if (!w) return null;
+  const next = { ...w, ...patch, expiresAt: Date.now() + WIZARD_TTL_MS };
+  wizardState.set(userId, next);
+  return next;
+}
+
+export function clearWizard(userId: number): void {
+  wizardState.delete(userId);
+}