Add webhook auto-verify example with runtime canonical receipt verification

examples/webhook-auto-verify/.gitignore

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+node_modules
+.env
+.DS_Store

examples/webhook-auto-verify/README.md

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+# Webhook Auto-Verification Example
+
+This example shows automatic verification. No manual paste is required.
+
+## Flow
+
+1. Runtime signs receipt.
+2. Webhook receives receipt.
+3. Server posts receipt to verifier.
+4. Valid receipt returns accepted.
+5. Tampered receipt returns rejected.
+
+## Commands
+
+```bash
+cd examples/webhook-auto-verify
+npm install
+npm run check
+npm run generate:samples
+npm start
+```
+
+In another terminal:
+
+```bash
+curl -X POST http://localhost:3000/webhook \
+  -H "Content-Type: application/json" \
+  --data @sample-canonical-shape-webhook.json
+
+curl -X POST http://localhost:3000/webhook \
+  -H "Content-Type: application/json" \
+  --data @sample-canonical-shape-tampered-webhook.json
+```
+
+Expected:
+- valid -> 200 accepted
+- tampered -> 400 rejected
+
+## Environment variables
+
+- `COMMANDLAYER_VERIFY_URL`
+- `COMMANDLAYER_SIGN_URL`
+- `PORT`
+
+## Trust boundaries
+
+- Runtime signs.
+- Verifier validates.
+- MCP bridges.
+- SDK wraps.
+- Schema-valid alone is not verified.
+- Verification requires hash and signature checks.
+- Webhook sender authentication is separate from receipt verification.
+
+
+## Note on sample files
+
+If your environment can reach `https://runtime.commandlayer.org`, run `npm run generate:samples` to create real live samples (`sample-valid-webhook.json` and `sample-tampered-webhook.json`).
+In offline or restricted environments, the committed `sample-canonical-shape-*.json` files are structure-only placeholders and are not verifiable runtime receipts.