fix: resolve all ESLint errors blocking CI releases

- Extract ThemeContext and ToolCollapseContext definitions into separate
  files to satisfy react-refresh/only-export-components rule
- Move useTheme and useToolCollapse hooks to dedicated hook files
- Fix empty catch block in ThemeContext (add comment)
- Replace Date.now() ref in ThinkingIndicator with useState initializer
- Update all imports across components

Closes feedback #58

src/components/ToolCall.tsx

@@ -3,7 +3,7 @@ import { ChevronRight, ChevronDown, Check, Copy, WrapText, AlignLeft } from 'luc
 import hljs from 'highlight.js/lib/common';
 import { useT } from '../hooks/useLocale';
 import { ImageBlock } from './ImageBlock';
-import { useToolCollapse } from '../contexts/ToolCollapseContext';
+import { useToolCollapse } from '../hooks/useToolCollapse';
 
 type ToolColor = { border: string; bg: string; text: string; icon: string; glow: string; expandBorder: string; expandBg: string };