feat(desktop): persistent needs-input indicator + icon button consolidation

Replace the background-clarify toast (expired on alt-tab, easy to miss) with a
persistent, glowing amber "needs input" dot on the session's sidebar row,
driven off a new ClientSessionState.needsInput flag mirrored into a
$attentionSessionIds store. The flag is set on clarify.request and cleared the
moment the turn resumes (tool.complete) or ends.

Also: redesign the clarify tool UI (borderless choices, pseudo-radio dots,
right-aligned checkmark, arc border, tighter padding), make Button the single
source of icon-button styling (4px radius, new icon-titlebar variant, titlebar
buttons rendered polymorphically via asChild, Codicons throughout), put the
file-tree refresh action first, and .trim() pasted composer text.

apps/desktop/src/app/session/hooks/use-message-stream.ts

@@ -531,7 +531,8 @@ export function useMessageStream({
           streamId: null,
           pendingBranchGroup: null,
           awaitingResponse: false,
-          busy: false
+          busy: false,
+          needsInput: false
         }
       })
 
@@ -588,7 +589,8 @@ export function useMessageStream({
           pendingBranchGroup: null,
           sawAssistantPayload: true,
           awaitingResponse: false,
-          busy: false
+          busy: false,
+          needsInput: false
         }
       })
     },
@@ -786,6 +788,11 @@ export function useMessageStream({
         if (sessionId) {
           flushQueuedDeltas(sessionId)
           upsertToolCall(sessionId, toTodoPayload(payload) ?? payload, 'complete', event.type)
+          // A pending clarify blocks the turn, so the first tool.complete after
+          // one is the clarify resolving — drop the "needs input" flag here so
+          // the sidebar indicator clears as soon as it's answered, not only at
+          // message.complete.
+          updateSessionState(sessionId, state => (state.needsInput ? { ...state, needsInput: false } : state))
         }
 
         if (typeof payload?.inline_diff === 'string' && payload.inline_diff.trim()) {
@@ -829,13 +836,11 @@ export function useMessageStream({
 
           // The transcript only renders the active session, so a background
           // clarify is otherwise invisible (the row just keeps spinning like
-          // it's working). Nudge the user toward the chat that needs them.
-          if (!isActiveEvent) {
-            notify({
-              kind: 'info',
-              title: 'Another chat needs input',
-              message: 'Hermes asked a question in a background session. Open it to answer.'
-            })
+          // it's working). Flag the session so the sidebar shows a persistent
+          // "needs input" indicator on its row — works for the active session
+          // too, and survives alt-tab / window blur (unlike a toast).
+          if (sessionId) {
+            updateSessionState(sessionId, state => ({ ...state, needsInput: true }))
           }
         }
       } else if (event.type === 'approval.request') {

apps/desktop/src/app/session/hooks/use-session-state-cache.ts

@@ -4,7 +4,7 @@ import { type MutableRefObject, useCallback, useEffect, useRef } from 'react'
 import type { ChatMessage } from '@/lib/chat-messages'
 import { preserveLocalAssistantErrors } from '@/lib/chat-messages'
 import { createClientSessionState } from '@/lib/chat-runtime'
-import { $busy, $messages, noteSessionActivity, setSessionWorking } from '@/store/session'
+import { $busy, $messages, noteSessionActivity, setSessionAttention, setSessionWorking } from '@/store/session'
 
 import type { ClientSessionState } from '../../types'
 
@@ -152,7 +152,12 @@ export function useSessionStateCache({
         setSessionWorking(previous.storedSessionId, false)
       }
 
+      if (previous.storedSessionId !== next.storedSessionId || !next.needsInput) {
+        setSessionAttention(previous.storedSessionId, false)
+      }
+
       setSessionWorking(next.storedSessionId, next.busy)
+      setSessionAttention(next.storedSessionId, next.needsInput)
       // Every state update is effectively a "still alive" heartbeat for
       // streaming events. The session-store watchdog uses this to keep the
       // working flag alive during long-running turns and to clear it once