feat: Lightning channel backup, Web5 mobile tab active, file path fix

Task 14: Lightning Channel Backup
- New lnd.export-channel-backup RPC — exports SCB (Static Channel Backup)
- Settings UI: "Lightning Channel Backup" section with export + copy
- Returns base64 backup data, channel count, timestamp

Web5 mobile tab active state
- Fixed combined tab matching for Web5: includes /web5, /federation, /mesh routes
- Previously only matched /cloud and /server (wrong branch)

Content file path fix
- Allow forward slashes in filenames for subdirectories (Music/song.mp3)
- Still block .., \, null bytes, hidden files, absolute paths

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/src/views/Dashboard.vue

@@ -304,7 +304,9 @@
             'nav-tab-active': item.isCombined
               ? (item.path === '/dashboard/apps'
                   ? (route.path.includes('/apps') || route.path.includes('/marketplace') || route.path.includes('/discover') || route.path.includes('/app-session'))
-                  : (route.path.includes('/cloud') || route.path.includes('/server')))
+                  : item.path === '/dashboard/web5'
+                    ? (route.path.includes('/web5') || route.path.includes('/federation') || route.path.includes('/mesh'))
+                    : (route.path.includes('/cloud') || route.path.includes('/server')))
               : undefined
           }"
           :exact-active-class="item.isCombined ? undefined : 'nav-tab-active'"

neode-ui/src/views/Settings.vue

@@ -955,6 +955,26 @@
       </div>
     </Teleport>
 
+    <!-- Lightning Channel Backup -->
+    <div class="glass-card px-6 py-6 mb-6">
+      <h2 class="text-xl font-semibold text-white/96 mb-1">Lightning Channel Backup</h2>
+      <p class="text-sm text-white/60 mb-3">Export your channel state so you can restore channels on a new node. Does not include on-chain wallet seed.</p>
+      <div class="flex gap-3">
+        <button @click="exportChannelBackup" :disabled="exportingChannelBackup" class="glass-button px-4 py-2 rounded-lg text-sm flex items-center gap-2">
+          <svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4" />
+          </svg>
+          {{ exportingChannelBackup ? 'Exporting...' : 'Export Channel Backup' }}
+        </button>
+      </div>
+      <div v-if="channelBackupData" class="mt-3 bg-black/30 rounded-lg p-3">
+        <p class="text-xs text-white/40 mb-1">{{ channelBackupChannels }} channel{{ channelBackupChannels !== 1 ? 's' : '' }} backed up at {{ channelBackupTime }}</p>
+        <textarea readonly :value="channelBackupData" rows="3" class="w-full bg-black/20 text-xs font-mono text-white/60 rounded p-2 resize-none border border-white/10"></textarea>
+        <button @click="copyChannelBackup" class="mt-2 glass-button px-3 py-1.5 rounded text-xs">{{ channelBackupCopied ? 'Copied!' : 'Copy Backup Data' }}</button>
+      </div>
+      <p v-if="channelBackupError" class="mt-2 text-xs text-red-400">{{ channelBackupError }}</p>
+    </div>
+
     <!-- Network Diagnostics Link -->
     <div class="glass-card px-6 py-6 mb-6">
       <div class="flex items-center justify-between">
@@ -1439,6 +1459,40 @@ interface BackupEntry {
 }
 const backupList = ref<BackupEntry[]>([])
 const loadingBackups = ref(false)
+
+// Lightning channel backup
+const exportingChannelBackup = ref(false)
+const channelBackupData = ref('')
+const channelBackupChannels = ref(0)
+const channelBackupTime = ref('')
+const channelBackupError = ref('')
+const channelBackupCopied = ref(false)
+
+async function exportChannelBackup() {
+  exportingChannelBackup.value = true
+  channelBackupError.value = ''
+  try {
+    const res = await rpcClient.call<{ backup: string; channel_count: number; timestamp: string }>({
+      method: 'lnd.export-channel-backup',
+      timeout: 15000,
+    })
+    channelBackupData.value = res.backup
+    channelBackupChannels.value = res.channel_count
+    channelBackupTime.value = new Date(res.timestamp).toLocaleString()
+  } catch (err: unknown) {
+    channelBackupError.value = err instanceof Error ? err.message : 'Failed to export'
+  } finally {
+    exportingChannelBackup.value = false
+  }
+}
+
+function copyChannelBackup() {
+  if (channelBackupData.value) {
+    navigator.clipboard.writeText(channelBackupData.value).catch(() => {})
+    channelBackupCopied.value = true
+    setTimeout(() => { channelBackupCopied.value = false }, 2000)
+  }
+}
 const showCreateBackupModal = ref(false)
 const backupPassphrase = ref('')
 const backupDescription = ref('')