fix: credential picker in host modal, fix xterm dimensions crash

- Added credential dropdown to New Host modal (loads from vault API)
- Fixed xterm.js "Cannot read dimensions" crash by guarding fitAddon.fit()
  with requestAnimationFrame and container dimension checks
- Added WebGL context loss handler
- credentialId now passed when creating hosts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/composables/useTerminal.ts

@@ -33,13 +33,23 @@ export function useTerminal() {
     term.open(container)
 
     try {
-      term.loadAddon(new WebglAddon())
+      const webgl = new WebglAddon()
+      webgl.onContextLoss(() => { webgl.dispose() })
+      term.loadAddon(webgl)
     } catch {
       // WebGL not available, fall back to canvas
     }
 
+    // Delay fit until container has layout dimensions
+    const safeFit = () => {
+      try {
+        if (container.offsetWidth > 0 && container.offsetHeight > 0) {
           fitAddon.fit()
-    const resizeObserver = new ResizeObserver(() => fitAddon.fit())
+        }
+      } catch { /* ignore fit errors on unmounted containers */ }
+    }
+    requestAnimationFrame(safeFit)
+    const resizeObserver = new ResizeObserver(() => safeFit())
     resizeObserver.observe(container)
 
     return { term, fitAddon, searchAddon, resizeObserver }

frontend/pages/index.vue

@@ -17,6 +17,10 @@ const selectedHost = ref<any>(null)
 const hostCredential = ref<any>(null)
 const loadingCredential = ref(false)
 
+// Credentials list for host modal dropdown
+const allCredentials = ref<any[]>([])
+const allSshKeys = ref<any[]>([])
+
 // Terminal composable for connect-on-click
 const { createTerminal, connectToHost } = useTerminal()
 
@@ -24,9 +28,18 @@ onMounted(async () => {
   await Promise.all([connections.fetchHosts(), connections.fetchTree()])
 })
 
-function openNewHost(groupId?: number) {
+async function openNewHost(groupId?: number) {
   editingHost.value = groupId ? { groupId } : null
-  inlineHost.value = { name: '', hostname: '', port: 22, protocol: 'ssh', groupId: groupId || null, tags: '' }
+  inlineHost.value = { name: '', hostname: '', port: 22, protocol: 'ssh', groupId: groupId || null, tags: '', credentialId: null }
+  // Load credentials for dropdown
+  try {
+    const [creds, keys] = await Promise.all([
+      vault.listCredentials() as Promise<any[]>,
+      vault.listKeys() as Promise<any[]>,
+    ])
+    allCredentials.value = creds
+    allSshKeys.value = keys
+  } catch { /* ignore */ }
   showHostDialog.value = true
 }
 
@@ -113,7 +126,7 @@ function dismissSavePrompt() {
 }
 
 // Inline modal state
-const inlineHost = ref({ name: '', hostname: '', port: 22, protocol: 'ssh' as 'ssh' | 'rdp', groupId: null as number | null, tags: '' })
+const inlineHost = ref({ name: '', hostname: '', port: 22, protocol: 'ssh' as 'ssh' | 'rdp', groupId: null as number | null, tags: '', credentialId: null as number | null })
 
 async function createGroupInline() {
   const nameEl = document.getElementById('grp-name') as HTMLInputElement
@@ -134,10 +147,11 @@ async function createHostInline() {
     port: inlineHost.value.port,
     protocol: inlineHost.value.protocol,
     groupId: inlineHost.value.groupId,
+    credentialId: inlineHost.value.credentialId,
     tags,
   })
   showHostDialog.value = false
-  inlineHost.value = { name: '', hostname: '', port: 22, protocol: 'ssh', groupId: null, tags: '' }
+  inlineHost.value = { name: '', hostname: '', port: 22, protocol: 'ssh', groupId: null, tags: '', credentialId: null }
   await connections.fetchTree()
 }
 
@@ -419,6 +433,15 @@ async function deleteSelectedHost() {
               <option value="rdp">RDP</option>
             </select>
           </div>
+          <div>
+            <label class="block text-sm text-gray-400 mb-1">Credential</label>
+            <select v-model="inlineHost.credentialId" class="w-full px-3 py-2 bg-gray-800 border border-gray-700 rounded text-white">
+              <option :value="null">— None —</option>
+              <option v-for="cred in allCredentials" :key="cred.id" :value="cred.id">
+                {{ cred.name }} ({{ cred.username || cred.type }})
+              </option>
+            </select>
+          </div>
           <div>
             <label class="block text-sm text-gray-400 mb-1">Tags <span class="text-gray-600">(comma separated)</span></label>
             <input v-model="inlineHost.tags" type="text" placeholder="ssh, prod, web"