feat: improve chat streaming UX and add Mermaid diagram rendering (#438)

* feat: show current branch in empty chat state

* fix: display current git branch for worktrees and update them with branch change

* refactor: improve read tool output parsing with structured data

* feat: add support for message part delta events

* fix(chat): improve streaming rendering, scroll behavior, and assistant action visibility

* feat: Add mermaid diagram support to chat markdown rendering

* fix: update table download functionality to include success notification and remove unused MarkdownRenderer import

* refactor: streamline Streamdown component props for improved readability

* fix: preserve Streamdown code-block markers and use native Tauri cache clearing

* feat: add context overview panel to view conversation details

packages/ui/src/components/chat/ChatEmptyState.tsx

@@ -1,8 +1,12 @@
 import React from 'react';
+import { RiGitBranchLine } from '@remixicon/react';
 
 import { OpenChamberLogo } from '@/components/ui/OpenChamberLogo';
 import { TextLoop } from '@/components/ui/TextLoop';
 import { useThemeSystem } from '@/contexts/useThemeSystem';
+import { useRuntimeAPIs } from '@/hooks/useRuntimeAPIs';
+import { useEffectiveDirectory } from '@/hooks/useEffectiveDirectory';
+import { useGitStatus, useGitStore } from '@/stores/useGitStore';
 
 const phrases = [
     "Fix the failing tests",
@@ -23,15 +27,51 @@ const phrases = [
     "Add type definitions",
 ];
 
-const ChatEmptyState: React.FC = () => {
+interface ChatEmptyStateProps {
+    showDraftContext?: boolean;
+}
+
+const ChatEmptyState: React.FC<ChatEmptyStateProps> = ({
+    showDraftContext = false,
+}) => {
     const { currentTheme } = useThemeSystem();
+    const { git } = useRuntimeAPIs();
+    const effectiveDirectory = useEffectiveDirectory();
+    const { setActiveDirectory, fetchStatus } = useGitStore();
+    const gitStatus = useGitStatus(effectiveDirectory ?? null);
 
     // Use theme's muted foreground for secondary text
     const textColor = currentTheme?.colors?.surface?.mutedForeground || 'var(--muted-foreground)';
+    const branchName = typeof gitStatus?.current === 'string' && gitStatus.current.trim().length > 0
+        ? gitStatus.current.trim()
+        : null;
+
+    React.useEffect(() => {
+        if (!showDraftContext || !effectiveDirectory) {
+            return;
+        }
+
+        setActiveDirectory(effectiveDirectory);
+
+        const state = useGitStore.getState().directories.get(effectiveDirectory);
+        if (!state?.status && state?.isGitRepo !== false) {
+            void fetchStatus(effectiveDirectory, git, { silent: true });
+        }
+    }, [effectiveDirectory, fetchStatus, git, setActiveDirectory, showDraftContext]);
 
     return (
         <div className="flex flex-col items-center justify-center min-h-full w-full gap-6">
             <OpenChamberLogo width={140} height={140} className="opacity-20" isAnimated />
+            {showDraftContext && (
+                <div className="max-w-[calc(100%-2rem)] flex flex-col items-center gap-1">
+                    {branchName && (
+                        <div className="inline-flex items-center gap-1 text-body-md" style={{ color: textColor }}>
+                            <RiGitBranchLine className="h-4 w-4 shrink-0" />
+                            <span className="overflow-hidden whitespace-nowrap" title={branchName}>{branchName}</span>
+                        </div>
+                    )}
+                </div>
+            )}
             <TextLoop
                 className="text-body-md"
                 interval={4}