Add NATS account-balance SoT and statement review for customers, CS, and sales

Internal billing now uses verae.billing.* request-reply and pubs. zappier-account-balance tracks prepaid, credits, usage, and payments. Portal, admin, CS, and sales all review the same statement. Independent Forgejo repos stay split via push-module-repos.

docs/modules/zappier/statement.md

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+# `zappier/statement`
+
+**Package:** `zappier`  
+**Source:** `packages/zappier/src/statement.ts`  
+**Lines:** 39
+
+## What this module is
+
+Implementation module in `zappier`. The tables below are extracted from the source (signatures + JSDoc).
+
+## Exports
+
+`composeStatement`
+
+## Types / interfaces / classes
+
+_None extracted._
+
+## Functions
+
+| Name | Parameters | Param types (JSDoc) | Returns | Calls (same file / helpers) |
+|------|------------|---------------------|---------|-----------------------------|
+| `composeStatement` | `args: {
+  customerId: string;
+  prepaidCents: number;
+  credits: CreditAdjustment[];
+  usage: UsageEntry[];
+  invoices: Invoice[];
+}` | — | `unknown` | see Call graph |
+
+## What it imports / requires
+
+- `./credits`
+- `./invoicing`
+- `./usage`
+
+## Call graph (identifiers invoked)
+
+`composeStatement`, `filter`, `map`, `now`, `toISOString`, `slice`, `reverse`
+
+Each identifier is a call site in this file. Follow the import list to see the defining module; open that module’s MD for parameter and return types.
+
+## Return values (how to read this)
+
+- HTTP route handlers return Express `res.json(...)` bodies (see route docs).
+- Zapier `perform` functions return a **single object** (creates) or an **array** (triggers/searches).
+- Pricing functions return integer **cents** on `Quote.totalCents`.
+