Skip zcash node loading and migration step 55 (chain removed)

The zcash chain was removed (cw_zcash deleted, assets/zcash_node_list.yml
deleted), but two places still tried to load it at runtime:

1. lib/entities/node_list.dart's resetToDefault() unconditionally called
   loadDefaultNodes(WalletType.zcash) which tried to read the deleted YAML.
2. lib/entities/default_settings_migration.dart migration step 55 called
   addWalletNodeList(type: WalletType.zcash) + _changeDefaultNode for zcash,
   same failure.

Both surfaced as a 'Unable to load asset: assets/zcash_node_list.yml' error
popup on every fresh wallet creation. Removing both call sites; migration
step 55 becomes a no-op (existing wallets advance through it without effect).

Also includes the new SVG variants added to assets/images/hash_wallet/:
03/04/05_*_dark.svg, 09_mark_outline.svg, 10_wordmark_only.svg,
11_vertical_lockup.svg, 12_notification_mono.svg — fills out the brand
kit with dark-theme wordmarks plus tiny/outline/wordmark-only/vertical/
notification variants for cases the existing set didn't cover.

assets/images/hash_wallet/03_lockup_horizontal_dark.svg

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 360 100" width="360" height="100">
+<title>Hash Wallet horizontal lockup (dark theme)</title>
+<desc>Hash Wallet logo with green-boxed hash mark on the left and a white wordmark to the right, intended for dark-theme backgrounds.</desc>
+<rect x="10" y="18" width="64" height="64" rx="14" fill="#1a5c38"/>
+<text x="42" y="68" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="48" font-weight="700" fill="#ffffff" text-anchor="middle">#</text>
+<text x="90" y="63" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="32" font-weight="500" fill="#ffffff">Hash Wallet</text>
+</svg>

assets/images/hash_wallet/04_hash_wallet_inline_dark.svg

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 380 80" width="380" height="80">
+<title>#ash Wallet — inline lockup (dark theme)</title>
+<desc>Hash Wallet inline lockup spelling "#ash Wallet" with white text, intended for dark-theme backgrounds.</desc>
+<rect x="6" y="14" width="52" height="52" rx="11" fill="#1a5c38"/>
+<text x="32" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="40" font-weight="700" fill="#ffffff" text-anchor="middle">#</text>
+<text x="68" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="42" font-weight="500" fill="#ffffff">ash Wallet</text>
+</svg>

assets/images/hash_wallet/05_function_lockup_dark.svg

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 500 80" width="500" height="80">
+<title>H(ash) = Wallet (dark theme)</title>
+<desc>Hash Wallet function-joke wordmark with green-boxed hash as the function name, light-on-dark variant. Punctuation/operators in mid-gray that reads on either background; argument and return in white.</desc>
+<rect x="6" y="14" width="52" height="52" rx="11" fill="#1a5c38"/>
+<text x="32" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="40" font-weight="700" fill="#ffffff" text-anchor="middle">#</text>
+<text x="68" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="40" font-weight="400" fill="#aaa">(</text>
+<text x="88" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="40" font-weight="500" fill="#ffffff">ash</text>
+<text x="158" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="40" font-weight="400" fill="#aaa">)</text>
+<text x="186" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="40" font-weight="400" fill="#aaa">=</text>
+<text x="218" y="55" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="40" font-weight="500" fill="#7fcaa0">Wallet</text>
+</svg>

assets/images/hash_wallet/09_mark_outline.svg

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" width="100" height="100">
+<title>Hash Wallet mark — outline</title>
+<desc>The Hash Wallet mark as a green outline + green hash, no fill. For monochrome UI surfaces and tiny sizes where the solid green box overwhelms.</desc>
+<rect x="4" y="4" width="92" height="92" rx="20" fill="none" stroke="#1a5c38" stroke-width="6"/>
+<text x="50" y="76" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="74" font-weight="700" fill="#1a5c38" text-anchor="middle">#</text>
+</svg>

assets/images/hash_wallet/10_wordmark_only.svg

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 280 60" width="280" height="60">
+<title>Hash Wallet wordmark</title>
+<desc>The Hash Wallet wordmark in mono, no mark — for headers, footers, or surfaces that already display the logo elsewhere. Uses currentColor so the consuming theme picks the tint.</desc>
+<text x="0" y="44" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="36" font-weight="500" fill="currentColor">Hash Wallet</text>
+</svg>

assets/images/hash_wallet/11_vertical_lockup.svg

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 240" width="200" height="240">
+<title>Hash Wallet vertical lockup</title>
+<desc>Hash Wallet logo with green-boxed hash mark on top, wordmark centered below — for splash screens, about screens, vertical-aspect surfaces. Wordmark uses currentColor for theme adaptability.</desc>
+<rect x="50" y="20" width="100" height="100" rx="22" fill="#1a5c38"/>
+<text x="100" y="96" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="74" font-weight="700" fill="#ffffff" text-anchor="middle">#</text>
+<text x="100" y="180" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="28" font-weight="500" fill="currentColor" text-anchor="middle">Hash Wallet</text>
+</svg>

assets/images/hash_wallet/12_notification_mono.svg

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="24" height="24">
+<title>Hash Wallet notification mark</title>
+<desc>Single-color silhouette of the hash mark, no background, sized for Android notification tray (24x24 dp). Renders as white-on-system-tint per Android notification icon rules.</desc>
+<text x="12" y="20" font-family="ui-monospace, 'JetBrains Mono', 'Courier New', monospace" font-size="22" font-weight="700" fill="currentColor" text-anchor="middle">#</text>
+</svg>

lib/entities/default_settings_migration.dart

@@ -563,13 +563,10 @@ Future<void> defaultSettingsMigration(
           await _backupWowneroSeeds(havenSeedStore);
           break;
         case 55:
-          await addWalletNodeList(nodes: nodes, type: WalletType.zcash);
-          await _changeDefaultNode(
-            nodes: nodes,
-            sharedPreferences: sharedPreferences,
-            type: WalletType.zcash,
-            currentNodePreferenceKey: PreferencesKey.currentZcashNodeIdKey,
-          );
+          // Hash Wallet: zcash removed. The original migration here added
+          // zcash node list + set default zcash node. We no longer load
+          // zcash_node_list.yml (it was deleted), so skip the whole step.
+          break;
         case 56:
           await sharedPreferences.setString(
               PreferencesKey.syncStatusDisplayMode, SyncStatusDisplayMode.blocksRemaining.name);