Scope site connection permissions per address

allowedSites and deniedSites are now objects keyed by address instead
of flat arrays, so approving a site for one address no longer grants
access for all addresses. Old flat-array data is discarded on load.
Settings view collects unique hostnames across all addresses and
deleting removes the site from every address.

src/shared/state.js

@@ -15,8 +15,8 @@ const DEFAULT_STATE = {
     blockscoutUrl: DEFAULT_BLOCKSCOUT_URL,
     lastBalanceRefresh: 0,
     activeAddress: null,
-    allowedSites: [],
-    deniedSites: [],
+    allowedSites: {},
+    deniedSites: {},
     rememberSiteChoice: true,
 };
 
@@ -54,8 +54,14 @@ async function loadState() {
             saved.blockscoutUrl || DEFAULT_STATE.blockscoutUrl;
         state.lastBalanceRefresh = saved.lastBalanceRefresh || 0;
         state.activeAddress = saved.activeAddress || null;
-        state.allowedSites = saved.allowedSites || [];
-        state.deniedSites = saved.deniedSites || [];
+        state.allowedSites =
+            saved.allowedSites && !Array.isArray(saved.allowedSites)
+                ? saved.allowedSites
+                : {};
+        state.deniedSites =
+            saved.deniedSites && !Array.isArray(saved.deniedSites)
+                ? saved.deniedSites
+                : {};
         state.rememberSiteChoice =
             saved.rememberSiteChoice !== undefined
                 ? saved.rememberSiteChoice