LinkSpin test area: InstantAdPay engine fork rebranded, network registry, sponsor carry-over with engine activation and claim window, rotator with /r/ redirects, link-domain mini-sites

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

README.md

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+# LinkSpin — site
+
+Membership advertising with immutable on-chain settlement. Zero-dependency
+Node server (RM Circle pattern): static pages + JSON API + SSE ledger.
+
+## Architecture
+
+- `server.js` — http server: pages, `/api/*`, `/join/<id>` sponsor links, SSE feed
+- `chain.js` — contract reader + persistent event indexer (free public RPCs)
+- `auth.js` — SIWE wallet sign-in (EIP-4361), sessions in the volume
+- `accounts.js` — site-side records only (free members, last-touch sponsor
+  attribution, handles). The CHAIN is the source of truth for money/credits.
+- `public/` — landing, live ledger, member area; no client libraries
+
+## Chain flip (rehearsal → mainnet)
+
+Everything chain-specific lives in `data/config.json` (volume):
+`{contract, chainId, chainName, explorer, rpcs, deployBlock}`.
+Defaults point at the **Amoy rehearsal** deployment. Launch = deploy the
+mainnet contract, wipe `accounts.json`/`sessions.json`/`chain-index.json`,
+PATCH `/api/admin/chain` with the mainnet values, set `rehearsal:false` via
+`/api/admin/site`. Same code, different config.
+
+## Run
+
+```
+PORT=3100 node server.js       # DATA_DIR defaults to ./data
+```
+
+Admin API auth: `Authorization: Bearer $ADMIN_PASSWORD`.
+
+Spec: `../CONTRACT-SPEC.md` (v1.0.3-frozen). Contracts: `../contracts/`.