fix: smooth message transitions, reliable scroll-to-bottom, permission mode icons

- Replace scrollIntoView with scrollTop=scrollHeight (fixes scroll jumping up
  on WS updates due to content-visibility: auto miscalculating positions)
- Watch messages array reference instead of .length to catch intermediate
  updates (tool calls resolving, content appended to existing messages)
- Add TransitionGroup for message list (outer) and assistant bubble content
  (inner) with non-scoped CSS to ensure classes reach child components
- Override content-visibility during transitions to prevent skipped frames
- Replace permission mode text badge with Unicode symbols matching Claude Code
  CLI: ⏵⏵ acceptEdits, ⏸ plan, ⚡ bypass, ⊘ dontAsk
- Remove lifecycle ribbon and agent status icon from bottom bar
- Use x-file-size header for knownByteSize instead of TextEncoder

frontend/src/components/transcript-debug/AssistantMessageBubble.vue

@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { computed } from 'vue'
+import { computed, TransitionGroup } from 'vue'
 import type { ParsedAssistantMessage } from '@/types/transcript-debug'
 import ThinkingBlock from './ThinkingBlock.vue'
 import ToolCallBlock from './ToolCallBlock.vue'
@@ -59,8 +59,10 @@ function formatTokens(n?: number): string {
       <span class="timestamp">{{ formatTime(message.timestamp) }}</span>
     </div>
 
+    <!-- All dynamic content in one TransitionGroup (fragment mode, no wrapper) -->
+    <TransitionGroup name="inner">
       <!-- Streaming/thinking animation -->
-    <div v-if="isStreaming" class="thinking-animation">
+      <div v-if="isStreaming" key="streaming" class="thinking-animation">
         <div class="thinking-dots">
           <span class="dot"></span>
           <span class="dot"></span>
@@ -83,8 +85,8 @@ function formatTokens(n?: number): string {
         :content="text"
       />
 
-    <!-- Tool calls -->
+      <!-- Tool calls (wrapped in div for TransitionGroup keying) -->
-    <template v-for="tc in message.toolCalls" :key="tc.id">
+      <div v-for="tc in message.toolCalls" :key="tc.id">
         <AskUserQuestionCard v-if="tc.name === 'AskUserQuestion'" :call="tc" />
         <ExitPlanModeCard v-else-if="tc.name === 'ExitPlanMode'" :call="tc" />
         <EnterPlanModeCard v-else-if="tc.name === 'EnterPlanMode'" :call="tc" />
@@ -96,7 +98,8 @@ function formatTokens(n?: number): string {
         <GlobCard v-else-if="tc.name === 'Glob'" :call="tc" />
         <TaskCard v-else-if="TASK_TOOLS.has(tc.name)" :call="tc" />
         <ToolCallBlock v-else :call="tc" />
-    </template>
+      </div>
+    </TransitionGroup>
   </div>
 </template>
 
@@ -213,4 +216,26 @@ function formatTokens(n?: number): string {
   word-break: break-word;
   margin: 0.25rem 0;
 }
+
+</style>
+
+<!-- Non-scoped: TransitionGroup classes must reach child component roots -->
+<style>
+.inner-enter-active {
+  transition: opacity 0.3s cubic-bezier(0.22, 1, 0.36, 1),
+              transform 0.3s cubic-bezier(0.22, 1, 0.36, 1);
+}
+
+.inner-enter-from {
+  opacity: 0;
+  transform: translateY(6px);
+}
+
+.inner-leave-active {
+  transition: opacity 0.12s ease;
+}
+
+.inner-leave-to {
+  opacity: 0;
+}
 </style>

frontend/src/components/transcript-debug/ChatContainer.vue

@@ -116,18 +116,19 @@ const hookHistory = computed(() => {
 // ── Derived display values ──
 const permissionMode = computed(() => props.hookPermissionMode || '')
 
-const PERMISSION_ICONS: Record<string, { icon: string; color: string; label: string; filled?: boolean }> = {
+// Permission mode display — matches Claude Code CLI indicators
-  default:           { icon: 'M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z', color: '#6b7280', label: 'Default — asks before risky actions' },
+const PERMISSION_DISPLAY: Record<string, { symbol: string; color: string; label: string; tight?: boolean }> = {
-  acceptEdits:       { icon: 'M17 3l4 4L7 21H3v-4z',                         color: '#4ade80', label: 'Accept Edits — auto-approves file changes' },
+  default:           { symbol: '●',  color: '#6b7280', label: 'Default' },
-  plan:              { icon: 'M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8zm11-3a3 3 0 1 0 0 6 3 3 0 0 0 0-6z', color: '#60a5fa', label: 'Plan — read-only, proposes before acting' },
+  acceptEdits:       { symbol: '⏵⏵', color: '#4ade80', label: 'Accept edits on', tight: true },
-  bypassPermissions: { icon: 'M13 2L3 14h9l-1 8 10-12h-9z', color: '#f87171', label: 'Bypass — auto-approves everything', filled: true },
+  plan:              { symbol: '⏸',  color: '#60a5fa', label: 'Plan mode on' },
-  dontAsk:           { icon: 'M18 6L6 18M6 6l12 12',         color: '#fb923c', label: 'Don\'t Ask — denies unless pre-approved' },
+  bypassPermissions: { symbol: '⚡', color: '#ff6eb4', label: 'Bypass permissions' },
+  dontAsk:           { symbol: '⊘',  color: '#fb923c', label: 'Don\'t ask' },
 }
 
-const permissionIcon = computed(() => {
+const permissionDisplay = computed(() => {
   const mode = permissionMode.value
   if (!mode) return null
-  return PERMISSION_ICONS[mode] || { icon: 'M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z', color: '#94a3b8', label: mode }
+  return PERMISSION_DISPLAY[mode] || { symbol: '?', color: '#94a3b8', label: mode }
 })
 const fullCwd = computed(() => props.conversation.metadata.cwd || '')
 const displayCwd = computed(() => {
@@ -734,12 +735,6 @@ function formatDuration(start: string, end: string): string {
     </Transition>
 
     <div class="bottom-overlay">
-      <SessionLifecycleStatus
-        :current-event="lifecycleEvent"
-        :event-detail="lifecycleDetail"
-        :hook-history="hookHistory"
-      />
-
       <UserInput
         :terminal-ready="props.terminalReady"
         :voice-transcript="voiceTranscript"
@@ -753,21 +748,9 @@ function formatDuration(start: string, end: string): string {
       />
 
       <div class="status-bar">
-      <span v-if="agentStatus" class="agent-status-icon" :class="{ processing: agentStatus.processing }">
+      <span v-if="permissionDisplay" class="perm-icon-wrap" :style="{ color: permissionDisplay.color }">
-        <svg width="12" height="12" viewBox="0 0 24 24"
+        <span class="perm-symbol" :class="{ tight: permissionDisplay.tight }">{{ permissionDisplay.symbol }}</span>
-          :fill="agentStatus.filled ? agentStatus.color : 'none'"
+        <span class="perm-tooltip">{{ permissionDisplay.label }}</span>
-          :stroke="agentStatus.filled ? 'none' : agentStatus.color"
-          stroke-width="2" stroke-linecap="round" stroke-linejoin="round"
-        ><path :d="agentStatus.icon" /></svg>
-        <span class="agent-status-tooltip">{{ agentStatus.tooltip }}</span>
-      </span>
-      <span v-if="permissionIcon" class="perm-icon-wrap">
-        <svg width="12" height="12" viewBox="0 0 24 24"
-          :fill="permissionIcon.filled ? permissionIcon.color : 'none'"
-          :stroke="permissionIcon.filled ? 'none' : permissionIcon.color"
-          stroke-width="2" stroke-linecap="round" stroke-linejoin="round"
-        ><path :d="permissionIcon.icon" /></svg>
-        <span class="perm-tooltip">{{ permissionIcon.label }}</span>
       </span>
       <span v-if="displayCwd" class="meta-badge origin" tabindex="0">{{ fullCwd }}</span>
       <span class="meta-count">{{ conversation.messages.length }} msgs</span>
@@ -958,18 +941,25 @@ function formatDuration(start: string, end: string): string {
   opacity: 1;
 }
 
-/* ── Permission mode icon ── */
+/* ── Permission mode symbol ── */
 .perm-icon-wrap {
   position: relative;
   display: inline-flex;
   align-items: center;
   justify-content: center;
-  width: 16px;
-  height: 16px;
   flex-shrink: 0;
   cursor: default;
 }
 
+.perm-symbol {
+  font-size: 10px;
+  line-height: 1;
+}
+
+.perm-symbol.tight {
+  letter-spacing: -0.35em;
+}
+
 .perm-tooltip {
   position: absolute;
   bottom: calc(100% + 5px);

frontend/src/composables/transcript-debug/useTranscriptDebug.ts

@@ -523,7 +523,7 @@ export function useTranscriptDebug() {
       const res = await apiFetch(`/api/transcript-debug/${selectedSessionId.value}/raw?agent=${selectedAgent.value}`)
       if (!res.ok) throw new Error(`HTTP ${res.status}`)
       rawContent.value = await res.text()
-      knownByteSize = new TextEncoder().encode(rawContent.value).length
+      knownByteSize = parseInt(res.headers.get('x-file-size') || res.headers.get('content-length') || '0', 10)
       const parsed = parseJsonl(rawContent.value, selectedSessionId.value)
       applyOptimisticState(parsed)
     } catch (e: any) {
@@ -623,7 +623,7 @@ export function useTranscriptDebug() {
       const res = await apiFetch(`/api/transcript-debug/${sessionId}/raw?agent=${agent}`)
       if (!res.ok) throw new Error(`HTTP ${res.status}`)
       rawContent.value = await res.text()
-      knownByteSize = new TextEncoder().encode(rawContent.value).length
+      knownByteSize = parseInt(res.headers.get('x-file-size') || res.headers.get('content-length') || '0', 10)
       conversation.value = parseJsonl(rawContent.value, sessionId)
       return true
     } catch (e: any) {