docs: add README + Open BSV LICENSE

LICENSE

@@ -0,0 +1,26 @@
+Open BSV License
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+1. This permission notice shall be included in all copies or substantial
+   portions of the Software.
+
+2. The Software, and any software that is derived from the Software or parts
+   thereof, can only be used on the Bitcoin SV blockchains. The Bitcoin SV
+   blockchains are defined, for purposes of this license, as the Bitcoin
+   blockchain containing block height #556767 with hash
+   000000000000000001d956714215d96ffc00e0afda4cd0a96c96f8d802b1662b and the
+   test blockchains that are compatible with it.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# margin-api
+
+[![CI](https://github.com/kryp2/margin-api/actions/workflows/ci.yml/badge.svg)](https://github.com/kryp2/margin-api/actions/workflows/ci.yml)
+[![License](https://img.shields.io/badge/license-Open%20BSV-blue.svg)](LICENSE)
+
+Orchestrator service for the Margin browser extension. It canonicalizes a target URL, builds a Bitcoin Schema draft, and produces a canonical AIP-signed `OP_RETURN` by coordinating two-phase signing with the Wallet Authentication Backend (WAB), then broadcasts the resulting transaction through an overlay service using a sponsor wallet.
+
+## How it works
+
+A single `POST /post` request drives the full pipeline:
+
+1. Canonicalize the submitted URL into a stable context URN.
+2. Resolve the user's signing identity from WAB (`/auth/margin/identity`) — no signing yet.
+3. Assemble the canonical AIP preimage (B + MAP + AIP header) with the resolved pubkey.
+4. Send the preimage to WAB (`/auth/margin/sign`) for a `sha256`/DER signature (BRC-77 lane).
+5. Append the signature to finalize the `OP_RETURN` script.
+6. Build the transaction with the sponsor wallet and submit it to the overlay.
+
+This two-phase split is required because the canonical AIP preimage must include the signing identity before the signature is computed.
+
+## Endpoints
+
+- `GET /health` — liveness plus sponsor-wallet status (address, balance, readiness).
+- `POST /post` — body `{ url, comment, id_token }`; returns `{ txid, script_hex, context_urn, signing_address, signing_pubkey, app }`. Rate-limited and capped at a 500-character comment (free tier).
+
+## Development
+
+```bash
+npm install      # install dependencies
+npm run dev      # run locally with ts-node-dev (auto-reload)
+npm run build    # compile TypeScript to dist/
+npm test         # run the Jest test suite
+npm run lint     # type-check only (tsc --noEmit)
+```
+
+## Configuration
+
+All configuration comes from environment variables (see `src/config.ts`):
+
+| Variable | Default | Description |
+| --- | --- | --- |
+| `PORT` | `8080` | HTTP listen port |
+| `BSV_NETWORK` | `main` | `main` or `test` |
+| `WAB_BASE_URL` | `https://wab.peck.to` | Wallet Authentication Backend |
+| `OVERLAY_BASE_URL` | `https://overlay.peck.to` | Overlay service base URL |
+| `OVERLAY_TOPIC` | `peck-schema` | Overlay topic to submit to |
+| `MARGIN_APP_NAME` | `margin` | App name written into the MAP record |
+| `CORS_ORIGINS` | `*` | Comma-separated allowed origins, or `*` |
+
+The sponsor wallet is configured via the `SPONSOR_PRIVATE_KEY_HEX`, `SPONSOR_INITIAL_UTXO`, and `SPONSOR_PARENT_TX_HEX` secrets.
+
+## Deployment
+
+A `Dockerfile` (multi-stage Node 20 build) and `cloudbuild.yaml` are provided for building and deploying to Cloud Run.
+
+## License
+
+[Open BSV License](LICENSE).

package.json

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   "name": "margin-api",
   "version": "0.1.0",
   "description": "Margin orchestrator: canonicalize URL → build draft → sign via WAB → assemble OP_RETURN",
-  "license": "MIT",
+  "license": "Open BSV",
   "main": "dist/index.js",
   "scripts": {
     "build": "tsc -p tsconfig.json",