feat: add message action hooks with TDD

Implement useMessageActions and useMessageUnreadCount hooks following strict TDD principles (RED → GREEN → REFACTOR).

useMessageActions provides:
- markRead(id) - mark single message as read
- batchMarkRead(ids) - batch mark messages as read
- deleteMessage(id) - delete message
- Independent loading/error states for each operation

useMessageUnreadCount provides:
- Fetch total unread count and counts by message type
- refetch() method for manual refresh
- loading and error state management

All operations use MessageController from SDK with proper error handling.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

hooks/use-message-actions.ts

@@ -0,0 +1,63 @@
+import { root } from '@repo/core'
+import { MessageController } from '@repo/sdk'
+import { useState } from 'react'
+
+export const useMessageActions = () => {
+  const [markReadLoading, setMarkReadLoading] = useState(false)
+  const [markReadError, setMarkReadError] = useState<Error | null>(null)
+  const [batchMarkReadLoading, setBatchMarkReadLoading] = useState(false)
+  const [batchMarkReadError, setBatchMarkReadError] = useState<Error | null>(null)
+  const [deleteLoading, setDeleteLoading] = useState(false)
+  const [deleteError, setDeleteError] = useState<Error | null>(null)
+
+  const markRead = async (id: string) => {
+    setMarkReadLoading(true)
+    setMarkReadError(null)
+    try {
+      const messageController = root.get(MessageController)
+      await messageController.markRead({ id })
+    } catch (error) {
+      setMarkReadError(error as Error)
+    } finally {
+      setMarkReadLoading(false)
+    }
+  }
+
+  const batchMarkRead = async (ids: string[]) => {
+    setBatchMarkReadLoading(true)
+    setBatchMarkReadError(null)
+    try {
+      const messageController = root.get(MessageController)
+      await messageController.batchMarkRead({ ids })
+    } catch (error) {
+      setBatchMarkReadError(error as Error)
+    } finally {
+      setBatchMarkReadLoading(false)
+    }
+  }
+
+  const deleteMessage = async (id: string) => {
+    setDeleteLoading(true)
+    setDeleteError(null)
+    try {
+      const messageController = root.get(MessageController)
+      await messageController.delete({ id })
+    } catch (error) {
+      setDeleteError(error as Error)
+    } finally {
+      setDeleteLoading(false)
+    }
+  }
+
+  return {
+    markRead,
+    markReadLoading,
+    markReadError,
+    batchMarkRead,
+    batchMarkReadLoading,
+    batchMarkReadError,
+    deleteMessage,
+    deleteLoading,
+    deleteError,
+  }
+}