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/store/db.md

@@ -0,0 +1,54 @@
+# `verae-zapier-middleware/store/db`
+
+**Package:** `verae-zapier-middleware`  
+**Source:** `packages/verae-zapier-middleware/src/store/db.js`  
+**Lines:** 115
+
+## What this module is
+
+Implementation module in `verae-zapier-middleware`. The tables below are extracted from the source (signatures + JSDoc).
+
+## Exports
+
+`emptyStore`, `loadStore`, `getStore`, `setStoreForTests`, `persist`, `reloadStore`
+
+## Types / interfaces / classes
+
+_None extracted._
+
+## Functions
+
+| Name | Parameters | Param types (JSDoc) | Returns | Calls (same file / helpers) |
+|------|------------|---------------------|---------|-----------------------------|
+| `emptyStore` | `(none)` | — | `StoreShape` | see Call graph |
+| `loadStore` | `path = config.storePath` | path: `string` | `StoreShape` | see Call graph |
+| `getStore` | `(none)` | — | `StoreShape` | see Call graph |
+| `setStoreForTests` | `next` | next: `StoreShape|null` | `void` | see Call graph |
+| `persist` | `path = config.storePath` | path: `string` | `void` | see Call graph |
+| `reloadStore` | `path = config.storePath` | path: `string` | `StoreShape` | see Call graph |
+
+## Methods (class / object)
+
+| Name | Parameters |
+|------|------------|
+| `writeFileSync` | `path, JSON.stringify(data, null, 2` |
+
+## What it imports / requires
+
+- `node:fs`
+- `node:path`
+- `../config.js`
+- `../debug/logger.js`
+
+## Call graph (identifiers invoked)
+
+`store`, `createDebugger`, `emptyStore`, `memory`, `loadStore`, `existsSync`, `readFileSync`, `parse`, `isArray`, `debug`, `keys`, `error`, `getStore`, `setStoreForTests`, `persist`, `dirname`, `mkdirSync`, `writeFileSync`, `stringify`, `disk`, `reloadStore`
+
+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`.
+