feat(UI): Adding a session manager (#3203)

# What does this PR do?

- Introduces the Agent Session creation for the Playground and allows
users to set tools
- note tools are actually not usable yet and this is marked explicitly
- this also caches sessions locally for faster loading on the UI and
deletes them appropriately
   - allows users to easily create new sessions as well
- Moved Model Configuration settings and "System Message" / Prompt to
the left component
- Added new logo and favicon
- Added new typing animation when LLM is generating

### Create New Session
<img width="1916" height="1393" alt="Screenshot 2025-08-21 at 4 18
08 PM"
src="https://github.com/user-attachments/assets/52c70ae3-a33e-4338-8522-8184c692c320"
/>


### List of Sessions
<img width="1920" height="1391" alt="Screenshot 2025-08-21 at 4 18
56 PM"
src="https://github.com/user-attachments/assets/ed78c3c6-08ec-486c-8bad-9b7382c11360"
/>

<!-- If resolving an issue, uncomment and update the line below -->
<!-- Closes #[issue-number] -->

## Test Plan
Unit tests added

---------

Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

llama_stack/ui/components/chat-playground/chat-message.tsx

@@ -161,10 +161,12 @@ export const ChatMessage: React.FC<ChatMessageProps> = ({
 
   const isUser = role === "user";
 
-  const formattedTime = createdAt?.toLocaleTimeString("en-US", {
-    hour: "2-digit",
-    minute: "2-digit",
-  });
+  const formattedTime = createdAt
+    ? new Date(createdAt).toLocaleTimeString("en-US", {
+        hour: "2-digit",
+        minute: "2-digit",
+      })
+    : undefined;
 
   if (isUser) {
     return (
@@ -185,7 +187,7 @@ export const ChatMessage: React.FC<ChatMessageProps> = ({
 
         {showTimeStamp && createdAt ? (
           <time
-            dateTime={createdAt.toISOString()}
+            dateTime={new Date(createdAt).toISOString()}
             className={cn(
               "mt-1 block px-1 text-xs opacity-50",
               animation !== "none" && "duration-500 animate-in fade-in-0"
@@ -220,7 +222,7 @@ export const ChatMessage: React.FC<ChatMessageProps> = ({
 
             {showTimeStamp && createdAt ? (
               <time
-                dateTime={createdAt.toISOString()}
+                dateTime={new Date(createdAt).toISOString()}
                 className={cn(
                   "mt-1 block px-1 text-xs opacity-50",
                   animation !== "none" && "duration-500 animate-in fade-in-0"
@@ -262,7 +264,7 @@ export const ChatMessage: React.FC<ChatMessageProps> = ({
 
       {showTimeStamp && createdAt ? (
         <time
-          dateTime={createdAt.toISOString()}
+          dateTime={new Date(createdAt).toISOString()}
           className={cn(
             "mt-1 block px-1 text-xs opacity-50",
             animation !== "none" && "duration-500 animate-in fade-in-0"