Milestone 1: Add Numbers Zapier app, /v1/add, developer setup guide

packages/verae-activate is pushable with zapier-platform 19.1.0: local
Add Numbers (number1+number2=sum) needs no hosted API. zapier-platform
validate is clean (0 warnings). zappier POST /v1/add is a free metered
endpoint for the optional hosted path.

Tests: verae-activate 7/7, zappier 176/176, verae-zapier 5/5, middleware
gate 1 11/11. Morning steps: docs/04-activate/SETUP-ZAPIER-DEVELOPER.md

Learned: perform runs on Zapier cloud so arithmetic needs no public URL;
CLI and zapier-platform-core majors must match; do not mix zapier-sdk.

docs/WORK-LOG.md

@@ -0,0 +1,22 @@
+# Work log
+
+Running record of milestones. Ordered by dependency.
+
+| ID | Item | Depends on | Status |
+|----|------|------------|--------|
+| M0 | Import zappier + middleware + research; git checkin | — | done `b4150c8` |
+| M1 | Organize layout + activate app + tests + Zapier setup guide | M0 | in progress |
+| M2 | Git checkin after green tests | M1 | pending |
+| M3 | Per-module MD (params, callees, returns) | M2 | pending |
+| M4 | Sphinx + PDF for every module | M3 | pending |
+| M5 | Git checkin docs + lessons | M4 | pending |
+| M6 | Integration hardening (`/v1/add` already on zappier) | M2 | partial |
+| M7 | Ready-to-activate final checkin | M5 | pending |
+
+## Learned (M1)
+
+- Zapier Platform `perform` runs in Zapier cloud. Add Numbers can be pure arithmetic so a first push needs **no public URL**.
+- CLI on this machine is `zapier-platform` 19.x; app core must match (`19.1.0`).
+- `zapier-platform validate` is structurally sound for `packages/verae-activate`.
+- Hosted path is optional: zappier `POST /v1/add` is free on the rate card (`operationId: add`).
+- Do not mix `zapier-sdk` (consume) with `zapier-platform` (publish).