Milestone 2: module/model docs (MD, Sphinx RST, PDF) and work log

74 source modules documented with extracted signatures, JSDoc params,
imports, and call graphs. 10 first-class models (PriceRule through
StatusResponse) have their own MD/RST/PDF. Sphinx HTML builds from
docs/sphinx. Per-module PDFs in docs/modules-pdf and docs/models-pdf.

Middleware gates 2–6 and 10 pass on MOCK_VERAE without NATS.

Learned: RST includes are relative to the RST file; keep one PDF per
module; Add Numbers remains the only push required tomorrow.

docs/modules/zappier/auth.md

@@ -0,0 +1,60 @@
+# `zappier/auth`
+
+**Package:** `zappier`  
+**Source:** `packages/zappier/src/auth.ts`  
+**Lines:** 84
+
+## What this module is
+
+Implementation module in `zappier`. The tables below are extracted from the source (signatures + JSDoc).
+
+## Exports
+
+`BillingType`, `Customer`, `CustomerRepo`, `InMemoryCustomerRepo`, `apiKeyAuth`
+
+## Types / interfaces / classes
+
+| Kind | Name |
+|------|------|
+| interface | `Customer` |
+| interface | `CustomerRepo` |
+| type | `BillingType` |
+| class | `InMemoryCustomerRepo` |
+
+## Functions
+
+| Name | Parameters | Param types (JSDoc) | Returns | Calls (same file / helpers) |
+|------|------------|---------------------|---------|-----------------------------|
+| `apiKeyAuth` | `repo: CustomerRepo` | — | `unknown` | see Call graph |
+
+## Methods (class / object)
+
+| Name | Parameters |
+|------|------------|
+| `findByApiKey` | `apiKey: string` |
+| `findByEmail` | `email: string` |
+| `list` | `(none)` |
+| `save` | `customer: Customer` |
+| `constructor` | `customers: Customer[] = []` |
+| `findByApiKey` | `apiKey: string` |
+| `findByEmail` | `email: string` |
+| `list` | `(none)` |
+| `save` | `customer: Customer` |
+| `return` | `req, res, next` |
+
+## What it imports / requires
+
+- `express`
+
+## Call graph (identifiers invoked)
+
+`findByApiKey`, `findByEmail`, `list`, `save`, `constructor`, `arrays`, `map`, `find`, `toLowerCase`, `findIndex`, `push`, `apiKeyAuth`, `header`, `status`, `json`, `next`
+
+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`.
+