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/verae-zapier-middleware/errors.md

@@ -0,0 +1,51 @@
+# `verae-zapier-middleware/errors`
+
+**Package:** `verae-zapier-middleware`  
+**Source:** `packages/verae-zapier-middleware/src/errors.js`  
+**Lines:** 76
+
+## What this module is
+
+Implementation module in `verae-zapier-middleware`. The tables below are extracted from the source (signatures + JSDoc).
+
+## Exports
+
+`AppError`, `asyncHandler`, `sendError`
+
+## Types / interfaces / classes
+
+| Kind | Name |
+|------|------|
+| class | `AppError` |
+
+## Functions
+
+| Name | Parameters | Param types (JSDoc) | Returns | Calls (same file / helpers) |
+|------|------------|---------------------|---------|-----------------------------|
+| `asyncHandler` | `fn` | fn: `(req: import('express').Request, res: import('express').Response, next: import('express').NextFunction) => Promise<unknown>` | `import('express').RequestHandler` | see Call graph |
+| `sendError` | `res, err` | res: `import('express').Response`, err: `Error|AppError` | `void` | see Call graph |
+
+## Methods (class / object)
+
+| Name | Parameters |
+|------|------------|
+| `constructor` | `message, { status = 500, code = 'INTERNAL_ERROR', details } = {}` |
+| `return` | `req, res, next` |
+
+## What it imports / requires
+
+- `./debug/logger.js`
+- `./debug/trace-context.js`
+
+## Call graph (identifiers invoked)
+
+`createDebugger`, `details`, `constructor`, `import`, `asyncHandler`, `resolve`, `fn`, `sendError`, `getTraceId`, `error`, `debug`, `status`, `json`
+
+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`.
+