feat: DID management UI in Federation — rotate DID + notify peers

- "My Node Identity" card shows DID with copy button
- "Rotate DID" button opens modal with password confirmation
- Rotation generates new keypair, then auto-notifies all federation peers
- Shows success/failure count after notification

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

neode-ui/src/views/Federation.vue

@@ -15,6 +15,42 @@
       <p class="text-sm text-white/60 mt-2">{{ nodes.length }} federated node{{ nodes.length !== 1 ? 's' : '' }}</p>
     </div>
 
+    <!-- My Node Identity -->
+    <div v-if="selfDid" class="glass-card p-4 mb-6">
+      <div class="flex items-center justify-between gap-4">
+        <div class="min-w-0 flex-1">
+          <p class="text-xs text-white/40 mb-1">Your Node DID</p>
+          <p class="text-sm text-white/70 font-mono truncate cursor-pointer" :title="selfDid" @click="copyDid">{{ selfDid }}</p>
+        </div>
+        <div class="flex items-center gap-2 shrink-0">
+          <button @click="copyDid" class="glass-button px-3 py-1.5 rounded-lg text-xs">Copy</button>
+          <button @click="showRotateModal = true" class="glass-button px-3 py-1.5 rounded-lg text-xs text-orange-300">Rotate DID</button>
+        </div>
+      </div>
+    </div>
+
+    <!-- Rotate DID Modal -->
+    <Teleport to="body">
+      <Transition name="modal">
+        <div v-if="showRotateModal" class="fixed inset-0 z-[3000] flex items-center justify-center p-4" @click.self="showRotateModal = false">
+          <div class="absolute inset-0 bg-black/60 backdrop-blur-sm"></div>
+          <div class="glass-card p-6 max-w-md w-full relative z-10">
+            <h3 class="text-lg font-semibold text-white mb-2">Rotate Node DID</h3>
+            <p class="text-sm text-white/60 mb-4">This generates a new identity keypair and notifies all federated peers. Your old DID will no longer be valid.</p>
+            <input v-model="rotatePassword" type="password" placeholder="Enter your password to confirm" class="w-full bg-black/30 border border-white/10 rounded-lg px-3 py-2 text-sm text-white placeholder-white/30 focus:outline-none focus:border-orange-500/50 mb-4" />
+            <p v-if="rotateError" class="text-red-400 text-xs mb-3">{{ rotateError }}</p>
+            <p v-if="rotateSuccess" class="text-green-400 text-xs mb-3">{{ rotateSuccess }}</p>
+            <div class="flex gap-3">
+              <button @click="showRotateModal = false; rotatePassword = ''; rotateError = ''; rotateSuccess = ''" class="flex-1 glass-button px-4 py-2 rounded-lg text-sm">Cancel</button>
+              <button @click="rotateDid" :disabled="rotatingDid || !rotatePassword" class="flex-1 glass-button px-4 py-2 rounded-lg text-sm font-medium bg-orange-500/20 border-orange-500/30 disabled:opacity-50">
+                {{ rotatingDid ? 'Rotating...' : 'Rotate & Notify Peers' }}
+              </button>
+            </div>
+          </div>
+        </div>
+      </Transition>
+    </Teleport>
+
     <!-- View Tabs -->
     <div v-if="nodes.length > 0" class="flex gap-1 mb-6 p-1 bg-black/20 rounded-lg w-fit">
       <button
@@ -679,6 +715,52 @@ function formatBytes(bytes?: number): string {
   return val.toFixed(1) + ' ' + units[i]
 }
 
+// DID rotation
+const showRotateModal = ref(false)
+const rotatePassword = ref('')
+const rotatingDid = ref(false)
+const rotateError = ref('')
+const rotateSuccess = ref('')
+
+function copyDid() {
+  if (selfDid.value) {
+    navigator.clipboard.writeText(selfDid.value).catch(() => {})
+  }
+}
+
+async function rotateDid() {
+  if (!rotatePassword.value) return
+  rotatingDid.value = true
+  rotateError.value = ''
+  rotateSuccess.value = ''
+  try {
+    const result = await rpcClient.call<{
+      old_did: string; new_did: string; proof_signature: string; proof_message: string
+    }>({ method: 'node.rotate-did', params: { password: rotatePassword.value } })
+
+    selfDid.value = result.new_did
+    rotateSuccess.value = `DID rotated. Notifying peers...`
+
+    // Notify federation peers
+    const notify = await rpcClient.call<{ notified: number; failed: number }>({
+      method: 'federation.notify-did-change',
+      params: {
+        old_did: result.old_did,
+        new_did: result.new_did,
+        proof_signature: result.proof_signature,
+        proof_message: result.proof_message,
+      },
+      timeout: 120000,
+    })
+    rotateSuccess.value = `DID rotated successfully. ${notify.notified} peers notified${notify.failed > 0 ? `, ${notify.failed} failed` : ''}.`
+    rotatePassword.value = ''
+  } catch (err: unknown) {
+    rotateError.value = err instanceof Error ? err.message : 'Rotation failed'
+  } finally {
+    rotatingDid.value = false
+  }
+}
+
 function formatUptime(secs: number): string {
   const days = Math.floor(secs / 86400)
   const hours = Math.floor((secs % 86400) / 3600)