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/reports.md

@@ -0,0 +1,56 @@
+# `zappier/reports`
+
+**Package:** `zappier`  
+**Source:** `packages/zappier/src/reports.ts`  
+**Lines:** 99
+
+## What this module is
+
+Implementation module in `zappier`. The tables below are extracted from the source (signatures + JSDoc).
+
+## Exports
+
+`BillingRow`, `billingRows`, `TrendPoint`, `usageTrend`, `CsvColumn`, `toCsv`
+
+## Types / interfaces / classes
+
+| Kind | Name |
+|------|------|
+| interface | `BillingRow` |
+| interface | `TrendPoint` |
+| interface | `CsvColumn` |
+
+## Functions
+
+| Name | Parameters | Param types (JSDoc) | Returns | Calls (same file / helpers) |
+|------|------------|---------------------|---------|-----------------------------|
+| `billingRows` | `args: {
+  entries: UsageEntry[];
+  customers: Customer[];
+  tiers: TierConfig[];
+  from?: Date;
+  to?: Date;
+  customerId?: string;
+  billingType?: BillingType;
+}` | — | `unknown` | see Call graph |
+| `usageTrend` | `entries: UsageEntry[], bucket: 'day' \| 'week'` | — | `unknown` | see Call graph |
+|  | _Day bucket: YYYY-MM-DD. Week bucket: the Monday (UTC) of that week, YYYY-MM-DD._ | | | |
+
+## What it imports / requires
+
+- `./auth`
+- `./pricing`
+- `./usage`
+
+## Call graph (identifiers invoked)
+
+`billingRows`, `filter`, `map`, `reduce`, `find`, `min`, `usageTrend`, `setUTCHours`, `getUTCDay`, `setUTCDate`, `getUTCDate`, `toISOString`, `slice`, `key`, `get`, `set`, `values`, `sort`, `localeCompare`, `test`, `replace`, `cell`, `join`, `push`
+
+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`.
+