fix: Blockscout and Etherscan lookups are off until the user turns them on (closes #668)

Out of the box the wallet sent the user's addresses to Blockscout and each recipient's address to Etherscan. Two settings, "Use Blockscout" and "Check recipients on Etherscan", now gate every request that sends the user's data to those services. Both start off and are offered unticked on Welcome and in Settings. Each request reads its setting from storage before it asks. An answer that lands after the setting went off is dropped. While a setting is off, the screens that rely on it say so. ENS lookups ask only the RPC endpoint, so a name resolved off-chain does not resolve.

RULES.md's External Communication item is now out of date. Its new wording will be proposed on #211 once this lands.

Model: opus-5-5 (implementation, summary); fable-5-1 (prose)

src/popup/views/send.js

@@ -10,6 +10,7 @@ const {
     renderAddressHtml,
     attachCopyHandlers,
     goBack,
+    tokenSourcesByChainId,
 } = require("./helpers");
 const { state, currentAddress } = require("../../shared/state");
 let ctx;
@@ -141,6 +142,8 @@ function updateToValidation() {
 }
 
 function renderSendTokenSelect(addr) {
+    // Only Blockscout reports the tokens the user has not tracked.
+    $("send-tokens-note").classList.toggle("hidden", !!state.useBlockscout);
     const sel = $("send-token");
     sel.innerHTML = `<option value="ETH">${escapeHtml(nativeCurrency())}</option>`;
     const fraudSet = new Set(
@@ -185,7 +188,9 @@ function renderSendTokenSelect(addr) {
 // so the transfer is encoded with the number the user read rather than with
 // whatever the contract answers at signing time (see
 // src/shared/transferAmount.js). balances.js is formatting one explorer row at
-// fetch time and cannot consult a state it is in the middle of replacing.
+// fetch time and cannot consult a state it is in the middle of replacing. As on
+// the approval screens, tokenSourcesByChainId() gives the wallets only while
+// "Use Blockscout" is on.
 //
 // The two resolutions can therefore differ, and where they do, the stored
 // `balance` is a quantity computed at a scale this screen has just declined to
@@ -198,10 +203,7 @@ function tokenBalanceAndDecimals(addr, token) {
     const tb = (addr.tokenBalances || []).find(
         (t) => t.address.toLowerCase() === token.toLowerCase(),
     );
-    const tokenDecimals = resolveTokenDecimals(token, {
-        trackedTokens: state.trackedTokens,
-        wallets: state.wallets,
-    });
+    const tokenDecimals = resolveTokenDecimals(token, tokenSourcesByChainId());
     if (!tb) return { tokenBalance: "0", tokenDecimals };
     if (tokenDecimals === null) return { tokenBalance: null, tokenDecimals };
     return { tokenBalance: tb.balance ?? null, tokenDecimals };
@@ -401,8 +403,11 @@ function init(_ctx) {
             try {
                 const provider = getProvider(state.rpcUrl, state.networkId);
                 const resolved = await provider.resolveName(to);
+                // getProvider() does not look up a name resolved off-chain,
+                // so such a name comes back with no address too. The message
+                // covers both, in the one line the flash area shows.
                 if (!resolved) {
-                    showFlash("That ENS name has no address.");
+                    showFlash("That ENS name has no on-chain address.");
                     return;
                 }
                 resolvedTo = resolved;
@@ -426,7 +431,7 @@ function init(_ctx) {
     });
 
     $("btn-send-back").addEventListener("click", () => {
-        $("send-token").classList.remove("hidden");
+        $("send-token-dropdown").classList.remove("hidden");
         $("send-token-static").classList.add("hidden");
         goBack();
     });