web-ui: full history on by default; trim trailing zeros on amounts

Blockbook history is enabled by default (existing configs migrated once
via a v2 marker; a later deliberate opt-out sticks). The in-panel opt-in
prompt is replaced by a one-line note when it is off.

All displayed DGB amounts go through one formatter: thousands separators,
trailing zeros trimmed, never fewer than two decimals (3,811.32468574,
5.00, 0.0003345). Amount-field values keep full precision.

packages/web-ui/src/ActivityList.tsx

@@ -1,4 +1,5 @@
 import { useState } from 'react';
+import { fmtSats } from './format.js';
 import type { DashboardUtxo } from './useWalletBalance.js';
 import type { BlockbookHistoryTx } from '@dgb-wallet/blockbook';
 import type { HistoryStatus } from './useWalletHistory.js';
@@ -60,17 +61,9 @@ export function ActivityList({
       </div>
 
       {historyStatus === 'disabled' && (
-        <div className="history-optin">
-          <div className="history-optin-body">
-            <strong>Want the full history?</strong>
-            <p>
-              Send + receive with dates comes from a Blockbook indexer. Enable it and the operator (<code>digibyte.atomicwallet.io</code>) will see the addresses this wallet queries.
-              Your seed and keys never leave this browser.
-            </p>
-          </div>
-          <button className="history-optin-btn" onClick={onEnableHistory}>
-            Enable full history
-          </button>
+        <div className="field-help" style={{ padding: '0 4px 10px' }}>
+          Full history is off (Settings → Connectivity → Blockbook).{' '}
+          <button className="text-btn" style={{ padding: 0 }} onClick={onEnableHistory}>Turn it on</button>
         </div>
       )}
 
@@ -343,15 +336,7 @@ function shortenAddr(a: string): string {
   return a.length <= 20 ? a : `${a.slice(0, 10)}…${a.slice(-6)}`;
 }
 
-function formatSats(sats: bigint): string {
-  // BigInt → 8-decimal DGB. Avoid Number rounding.
-  const neg = sats < 0n;
-  const abs = neg ? -sats : sats;
-  const s = abs.toString().padStart(9, '0');
-  const int = s.slice(0, -8);
-  const frac = s.slice(-8);
-  return `${neg ? '-' : ''}${Number(int).toLocaleString()}.${frac}`;
-}
+const formatSats = fmtSats;
 
 function formatTime(ms: number): string {
   const d = new Date(ms);

packages/web-ui/src/AssetsList.tsx

@@ -1,4 +1,5 @@
 import { DgbLogo } from './DgbLogo.js';
+import { fmtDgb } from './format.js';
 
 // Assets section. Today the only asset is native DGB. When
 // DigiAssets (Layer-2 token) support lands, each token becomes
@@ -13,8 +14,7 @@ export function AssetsList({
   loading: boolean;
 }): JSX.Element {
   const dgb = totalSats / 1e8;
-  const [intPart, fracPart] = dgb.toFixed(8).split('.');
-  const intFmt = Number(intPart).toLocaleString();
+  const [intFmt, fracPart = '00'] = fmtDgb(dgb).split('.');
 
   return (
     <section className="assets">

packages/web-ui/src/BalanceCard.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useState } from 'react';
+import { fmtDgb } from './format.js';
 import { DgbLogo } from './DgbLogo.js';
 import { WINDOW_CHOICES, type WindowChoice, type ScanDiagnostic } from './useWalletBalance.js';
 
@@ -164,12 +165,7 @@ export function BalanceCard({
 // 8-decimal fixed. Splits into integer + fractional so the CSS can
 // dim the low-order fraction (a common wallet UX to make small
 // balances feel less overwhelming).
-function formatDgb(dgb: number): string {
-  const rounded = Math.round(dgb * 1e8) / 1e8;
-  const [intPart, fracPart = '00000000'] = rounded.toFixed(8).split('.');
-  const intWithSep = Number(intPart).toLocaleString(undefined, { maximumFractionDigits: 0 });
-  return `${intWithSep}.${fracPart}`;
-}
+const formatDgb = (dgb: number): string => fmtDgb(dgb);
 
 function formatAge(ms: number): string {
   if (ms < 60_000) return `${Math.floor(ms / 1000)}s`;

packages/web-ui/src/Dashboard.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useState } from 'react';
+import { fmtSats } from './format.js';
 import {
   seedFromPhrase, rootFromSeed, accountNode, addressNode,
   addressesForPubkey, importWifWithAddresses,
@@ -411,12 +412,4 @@ function AddressesPanel({
   );
 }
 
-function formatSats(sats: bigint): string {
-  if (sats === 0n) return '0';
-  const neg = sats < 0n;
-  const abs = neg ? -sats : sats;
-  const s = abs.toString().padStart(9, '0');
-  const int = s.slice(0, -8);
-  const frac = s.slice(-8).replace(/0+$/, '');
-  return `${neg ? '-' : ''}${Number(int).toLocaleString()}${frac ? '.' + frac : ''}`;
-}
+const formatSats = fmtSats;

packages/web-ui/src/ImportScreen.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useMemo, useState } from 'react';
+import { fmtSats } from './format.js';
 import { PasswordInput } from './PasswordInput.js';
 import {
   validateSeedPhrase,
@@ -559,7 +560,5 @@ export function ImportScreen(): JSX.Element {
 }
 
 function fmt(sat: bigint | null): string {
-  if (sat === null) return '—';
-  const s = sat.toString().padStart(9, '0');
-  return `${Number(s.slice(0, -8)).toLocaleString()}.${s.slice(-8)}`;
+  return sat === null ? '—' : fmtSats(sat);
 }

packages/web-ui/src/PathSearchPanel.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useMemo, useState } from 'react';
+import { fmtSats } from './format.js';
 import { searchPaths, searchSingle, PATH_CANDIDATES, candidateKey, type PathHit, type PathCandidate } from './path-search.js';
 import { useActiveSeed } from './ActiveSeed.js';
 import {
@@ -269,7 +270,5 @@ export function PathSearchPanel(): JSX.Element | null {
 }
 
 function fmt(sat: bigint | null): string {
-  if (sat === null) return '—';
-  const s = sat.toString().padStart(9, '0');
-  return `${Number(s.slice(0, -8)).toLocaleString()}.${s.slice(-8)}`;
+  return sat === null ? '—' : fmtSats(sat);
 }

packages/web-ui/src/SendScreen.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useRef, useState } from 'react';
+import { fmtSats } from './format.js';
 import { PinConfirmModal } from './PinConfirmModal.js';
 import { useSessionAuth } from './session-auth.js';
 import {
@@ -258,7 +259,7 @@ export function SendScreen({
         // is extra fee — bounded by DUST_SATS + one output's fee share.
         const need = feeNoChange();
         if (inputSats < amtSats + need) {
-          throw new Error(`Insufficient funds: have ${(inputSats / 1e8).toFixed(8)}, need ${((amtSats + need) / 1e8).toFixed(8)} (incl. ${(need / 1e8).toFixed(8)} fee)`);
+          throw new Error(`Insufficient funds: have ${fmtSats(inputSats)}, need ${fmtSats(amtSats + need)} (incl. ${fmtSats(need)} fee)`);
         }
         changeAmt = 0;
         feeSats = inputSats - amtSats;
@@ -492,7 +493,7 @@ export function SendScreen({
         {pinPrompt && (
           <PinConfirmModal
             title="Confirm broadcast"
-            message={`Enter your session PIN to send ${(r.amountSats / 1e8).toFixed(8)} DGB.`}
+            message={`Enter your session PIN to send ${fmtSats(r.amountSats)} DGB.`}
             onConfirm={() => { setPinPrompt(false); void doBroadcast(); }}
             onCancel={() => setPinPrompt(false)}
           />
@@ -506,15 +507,15 @@ export function SendScreen({
           <span className="tx-k">To</span>
           <span className="tx-v"><code className="tx-mono">{r.recipient}</code></span>
           <span className="tx-k">Amount</span>
-          <span className="tx-v send-review-amount">{(r.amountSats / 1e8).toFixed(8)} DGB</span>
+          <span className="tx-v send-review-amount">{fmtSats(r.amountSats)} DGB</span>
           <span className="tx-k">Fee</span>
-          <span className="tx-v">{(r.feeSats / 1e8).toFixed(8)} DGB</span>
+          <span className="tx-v">{fmtSats(r.feeSats)} DGB</span>
           <span className="tx-k">Total out</span>
-          <span className="tx-v">{((r.amountSats + r.feeSats) / 1e8).toFixed(8)} DGB</span>
+          <span className="tx-v">{fmtSats(r.amountSats + r.feeSats)} DGB</span>
           <span className="tx-k">Change</span>
           <span className="tx-v">
             {status.changeAddress
-              ? <>{(r.change.reduce((s, c) => s + c.value, 0) / 1e8).toFixed(8)} DGB → <code className="tx-mono">{status.changeAddress}</code></>
+              ? <>{fmtSats(r.change.reduce((s, c) => s + c.value, 0))} DGB → <code className="tx-mono">{status.changeAddress}</code></>
               : 'none'}
           </span>
           <span className="tx-k">Inputs</span>
@@ -635,12 +636,12 @@ export function SendScreen({
         </div>
       </div>
       <div className="field-help">
-        Network fee: {FEE_RATE_SAT_PER_VB} sat/vB (DigiByte relays nothing under {MIN_RELAY_SAT_PER_VB}), about {(feeFor(estimateVbytes(['p2wpkh'], ['dgb1q', 'dgb1q'])) / 1e8).toFixed(5)} DGB for a typical send.
+        Network fee: {FEE_RATE_SAT_PER_VB} sat/vB (DigiByte relays nothing under {MIN_RELAY_SAT_PER_VB}), about {fmtSats(feeFor(estimateVbytes(['p2wpkh'], ['dgb1q', 'dgb1q'])))} DGB for a typical send.
         {' '}Change goes to {
           backendConfig.privacy.changePolicy === 'same' ? 'the address the coins were spent from'
           : backendConfig.privacy.changePolicy === 'fresh' ? 'a fresh address on the same derivation path as the coins spent'
           : 'your BIP84 bech32 change branch'} (Settings → Security).
-        {' '}Spendable now: {(availableSats / 1e8).toFixed(8)} DGB
+        {' '}Spendable now: {fmtSats(availableSats)} DGB
         {scanStatus === 'loading' ? ' (scan still running)' : ''}.
       </div>
 

packages/web-ui/src/backend-config.ts

@@ -74,7 +74,7 @@ const STORAGE_KEY = 'dgb-wallet:backend-config';
 
 const DEFAULT_CONFIG: BackendConfig = {
   p2p:       { scan: true,  broadcast: true  },
-  blockbook: { scan: false, broadcast: false },
+  blockbook: { scan: true,  broadcast: false },
   display:   { priceFeed: false, autoWidenScan: true, autoRefreshSec: 60 },
   privacy:   { freshAddresses: false, changePolicy: 'same' },
   security:  { requirePinOnSend: false },
@@ -84,12 +84,18 @@ function readStored(): BackendConfig {
   try {
     const raw = localStorage.getItem(STORAGE_KEY);
     if (!raw) return DEFAULT_CONFIG;
-    const parsed = JSON.parse(raw) as BackendConfig;
+    const parsed = JSON.parse(raw) as BackendConfig & { v?: number };
     // Fill missing keys from defaults so old stored configs stay
     // valid when we add capabilities.
+    // v2 (2026-10): full history became the default. Configs saved before
+    // that carry blockbook.scan=false only because it was the old default,
+    // not because anyone chose it — flip it once, then record v2 so a
+    // deliberate later opt-out sticks.
+    const blockbook = { ...DEFAULT_CONFIG.blockbook, ...(parsed.blockbook ?? {}) };
+    if ((parsed.v ?? 1) < 2) blockbook.scan = true;
     return {
       p2p: { ...DEFAULT_CONFIG.p2p, ...(parsed.p2p ?? {}) },
-      blockbook: { ...DEFAULT_CONFIG.blockbook, ...(parsed.blockbook ?? {}) },
+      blockbook,
       display: { ...DEFAULT_CONFIG.display, ...(parsed.display ?? {}) },
       privacy: { ...DEFAULT_CONFIG.privacy, ...(parsed.privacy ?? {}) },
       security: { ...DEFAULT_CONFIG.security, ...(parsed.security ?? {}) },
@@ -100,7 +106,7 @@ function readStored(): BackendConfig {
 }
 
 function writeStored(config: BackendConfig): void {
-  try { localStorage.setItem(STORAGE_KEY, JSON.stringify(config)); } catch { /* private mode */ }
+  try { localStorage.setItem(STORAGE_KEY, JSON.stringify({ ...config, v: 2 })); } catch { /* private mode */ }
 }
 
 // Context-backed store. Every consumer in the tree shares the same

packages/web-ui/src/format.ts

@@ -0,0 +1,22 @@
+// One rule for every DGB amount the wallet displays: integer part with
+// thousands separators, decimals trimmed of trailing zeros but never
+// fewer than MIN_DECIMALS. So 3,811.32468574 stays as is, 5.00000000
+// becomes 5.00, and 0.00033450 becomes 0.0003345. Exact: works on
+// satoshis as bigint, never through a float.
+const MIN_DECIMALS = 2;
+
+export function fmtSats(sats: bigint | number, min = MIN_DECIMALS): string {
+  const v = typeof sats === 'bigint' ? sats : BigInt(Math.round(sats));
+  const neg = v < 0n;
+  const abs = neg ? -v : v;
+  const s = abs.toString().padStart(9, '0');
+  const int = Number(s.slice(0, -8)).toLocaleString();
+  let frac = s.slice(-8).replace(/0+$/, '');
+  if (frac.length < min) frac = frac.padEnd(min, '0');
+  return `${neg ? '-' : ''}${int}${frac ? '.' + frac : ''}`;
+}
+
+/** Same rule for a DGB-denominated float (converted to sats first). */
+export function fmtDgb(dgb: number, min = MIN_DECIMALS): string {
+  return fmtSats(BigInt(Math.round(dgb * 1e8)), min);
+}