Root signing page and a root chain check for replacing the root keys (#81)

- signed_config.py root drafts a later root in docs/root-signing/proposals/,
  where wallets never look, and keeps the current targets key by default.
- docs/root-signing/: a page for the Pezkuwi Wallet DApp browser that shows
  the proposal and its fingerprint, has the holder's wallet sign
  <Bytes>payload</Bytes>, checks every signature as the wallet will, collects
  signature codes and offers root.N.json once two current and two new holders
  have signed. Crypto bundles are served beside it.
- scripts/root/verify_root.mjs checks every published signed/root.N.json the
  way installed wallets do; Code Quality runs it. Wallet 1.3.0 accepts sr25519
  only under the substrate signing context, and a root it cannot verify stops
  its config refresh, so such a root must never reach master.
- Draft root 2: three new holder accounts, threshold 2, five years.

.github/workflows/code-quality.yml

@@ -93,6 +93,18 @@ jobs:
       - name: Light client checkpoint not stale
         run: python3 scripts/light_client_specs.py --relay-rpc https://zagros-rpc.pezkuwichain.io --check-age 60
 
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+
+      # A wallet that finds a root it cannot verify stops refreshing its config, so every published
+      # signed/root.N.json is checked here exactly as installed wallets check it.
+      - name: Root chain verifies as installed wallets check it
+        run: |
+          npm ci --prefix scripts/root --ignore-scripts --no-audit --no-fund
+          node scripts/root/verify_root.mjs docs/root-signing/proposals/*.json
+
   chain-integrity:
     name: Chain Config Integrity
     runs-on: ubuntu-latest