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-accounting-export/server.md

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+# `zappier-accounting-export/server`
+
+**Package:** `zappier-accounting-export`  
+**Source:** `packages/zappier-accounting-export/src/server.js`  
+**Lines:** 62
+
+## What this module is
+
+Implementation module in `zappier-accounting-export`. The tables below are extracted from the source (signatures + JSDoc).
+
+## Exports
+
+_No named `export` / `module.exports` keys detected._
+
+## Types / interfaces / classes
+
+_None extracted._
+
+## Functions
+
+| Name | Parameters | Param types (JSDoc) | Returns | Calls (same file / helpers) |
+|------|------------|---------------------|---------|-----------------------------|
+| `edge` | `pathname` | — | `unknown` | see Call graph |
+| `send` | `code, type, body` | — | `unknown` | see Call graph |
+| `json` | `code, obj` | — | `unknown` | see Call graph |
+
+## What it imports / requires
+
+- `node:fs`
+- `node:http`
+- `node:path`
+- `node:url`
+- `./nats-billing.js`
+
+## Call graph (identifiers invoked)
+
+`replace`, `join`, `dirname`, `fileURLToPath`, `edge`, `fetch`, `createServer`, `async`, `writeHead`, `end`, `send`, `stringify`, `readFileSync`, `json`, `match`, `billingRequest`, `text`, `get`, `encodeURIComponent`, `listen`, `write`
+
+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`.
+