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/models/PriceRule.md

@@ -0,0 +1,26 @@
+# PriceRule
+
+**Kind:** discriminated union  
+**Defined in:** `packages/zappier/src/pricing.ts`
+
+## Fields
+
+| Field | Type | Meaning |
+|-------|------|---------|
+| `kind` | `'free' | 'fixed' | 'variable'` | Which list-price formula |
+| `fixedCents` | `number?` | When kind=fixed, cents per call |
+| `baseCents` | `number?` | When kind=variable, base cents |
+| `perKbCents` | `number?` | When kind=variable, per KB metadata |
+| `perMbCents` | `number?` | When kind=variable, per MB attachments |
+
+## Who constructs it
+
+RateCard.endpoints values
+
+## Who consumes it
+
+`quoteCall`, `meter`, `admin rate card UI`, `portal API & pricing tab`
+
+## Related modules
+
+See `docs/modules/` for the functions that take these types as parameters and the values they return.