refactor(cli): migrate UI state to ui-store

Complete the store migration by moving UI-related state to ui-store:
- focusedAgentId, inputFocused, setFocusedAgentId, setInputFocused
- Removes these from chat-store (now fully in ui-store)
- Final step in reducing prop drilling

All state now properly distributed across specialized stores:
- chat-store: messages, input value, agent mode, session state
- stream-store: streaming agents, chain progress
- queue-store: message queue, streaming status
- ui-store: UI state (focus, input)
- auth-store: authentication

All tests pass (231/231) and typecheck is clean.

Author: brandonkachen

cli/src/chat.tsx

@@ -42,6 +42,7 @@ import { logger } from './utils/logger'
 import { AnalyticsEvent } from '@codebuff/common/constants/analytics-events'
 import { useChatStore } from './state/chat-store'
 import { useStreamStore } from './state/stream-store'
+import { useUiStore } from './state/ui-store'
 import { createChatScrollAcceleration } from './utils/chat-scroll-accel'
 import { loadLocalAgents } from './utils/local-agent-registry'
 import { buildMessageTree } from './utils/message-tree-utils'
@@ -99,14 +100,10 @@ export const Chat = ({
     cursorPosition,
     lastEditDueToNav,
     setInputValue,
-    inputFocused,
-    setInputFocused,
     slashSelectedIndex,
     setSlashSelectedIndex,
     agentSelectedIndex,
     setAgentSelectedIndex,
-    focusedAgentId,
-    setFocusedAgentId,
     messages,
     setMessages,
     agentMode,
@@ -125,14 +122,10 @@ export const Chat = ({
       cursorPosition: store.cursorPosition,
       lastEditDueToNav: store.lastEditDueToNav,
       setInputValue: store.setInputValue,
-      inputFocused: store.inputFocused,
-      setInputFocused: store.setInputFocused,
       slashSelectedIndex: store.slashSelectedIndex,
       setSlashSelectedIndex: store.setSlashSelectedIndex,
       agentSelectedIndex: store.agentSelectedIndex,
       setAgentSelectedIndex: store.setAgentSelectedIndex,
-      focusedAgentId: store.focusedAgentId,
-      setFocusedAgentId: store.setFocusedAgentId,
       messages: store.messages,
       setMessages: store.setMessages,
       agentMode: store.agentMode,
@@ -158,6 +151,9 @@ export const Chat = ({
     setIsChainInProgress,
   } = useStreamStore()
 
+  const { focusedAgentId, setFocusedAgentId, inputFocused, setInputFocused } =
+    useUiStore()
+
   // Memoize toggle IDs extraction - only recompute when messages change
   const allToggleIds = useMemo(() => {
     const ids = new Set<string>()