Milestone 0: import zappier billing, Verae middleware, and Zapier research

Compose-ready workspace: packages/zappier (rate card, portal, Stripe),
packages/verae-zapier-middleware (timestamp + NATS), packages/verae-zapier
(CLI app), vendor/zapier-platform, and research/zapier vendor corpus.

Gate 0 structure checks pass. Product code and research are not yet wired.

vendor/zapier-platform/schema-to-ts/README.md

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+# Zapier Schema-to-TS
+
+This is a tool to convert the JSON Schema schemas from
+zapier-platform-schema into TypeScript types and interfaces that can be
+used in downstream integration application code.
+
+This tool is not intended to be pushed to NPM, but rather to be used
+during development of the Zapier Platform CLI. This is why it has been
+placed as a top-level package in this repo, and not in `packages/`.
+
+## Development
+
+- `pnpm install` for getting started.
+- `pnpm test` for running unit tests.
+- `pnpm build` for building this compiler into runnable js inside of `./dist/`.
+- `pnpm generate-types` to actually generate the TypeScript interfaces.
+  - By default, this will read `packages/schema/exported-schema.json` as input.
+  - By default, this will write `packages/core/types/zapier.generated.d.ts` as output.
+
+## "Publishing"
+
+This tool is configured via run `pnpm generate-types` on every commit,
+via husky. This will keep the generated TypeScript interfaces up to date
+with the latest schema definitions.
+
+## How it Works
+
+This tool reads the contents of `packages/schema/exported-schema.json`,
+and, starting with the AppSchema, recursively generates relevant types
+and interfaces that it references. Ultimately, it writes a
+`schemas.generated.d.ts` file in `packages/core/types/`. These types are
+referenced and combined with the other types of zapier-platform-core to
+provide a complete set of typings for integration developers to use.
+
+Notably, there is an "override" system in `overrides.ts` that allows for
+the raw types and interfaces to be modified or skipped as they are
+encountered during conversion from JSONSchema into TypeScript. The
+ts-morph library, a wrapper of TypeScript internals, is used to assemble
+and write the final output.
+
+## Rationale
+
+Converting our JSON Schema schemas into TypeScript interfaces has been a
+longstanding goal at Zapier (See issue
+[#8](https://github.com/zapier/zapier-platform/issues/8) and
+[#233](https://github.com/zapier/zapier-platform/issues/233)).
+While the JSON schemas exist and are useful at the point of uploading
+integrations to the Zapier platform, AND the fact there are plenty of
+open-source schema TypeScript projects, none would address the fact that
+there are features of JavaScript that are necessary when writing a
+Zapier CLI integration. Specifically, our JSON Schemas are unable to
+express the concepts of functions or promises, or connect the
+definitions of input field definitions to the data provided in
+bundle.inputData objects in perform functions.
+
+In a similar vein, previous attempts, even to use the
+`json-schema-to-typescript` library have floundered, as the level of
+documentation and references it provides were undesirable. This project
+was born as a HackWeek project in April 2024 to address some of these
+issues, and has since been refined and improved.
+
+This schema-to-ts project was rewritten in April 2025 to introduce the
+much neater override system and any remove all dependency on the
+`json-schema-to-typescript` library.