fix(docs): adding chat readme and info in changelog (#16583)

Author: ChronosSF

CHANGELOG.md

@@ -4,23 +4,14 @@ All notable changes for each version of this project will be documented in this
 
 ## 21.0.0
 
-### Themes
-
-- `IgxButton`
-    - **Breaking Change**
-        - The following shadow-related parameters were removed from the `outlined-button-theme` and `flat-button-theme`:
-            - `resting-shadow`
-            - `hover-shadow`
-            - `focus-shadow`
-            - `active-shadow`
-
-## 21.0.0
-
 ### New Features
 
+- **New component** `IgxChat`:
+    - A component that provides complete solution for building conversational interfaces in your applications. Read up more information in the [ReadMe](https://github.com/IgniteUI/igniteui-angular/tree/master/projects/igniteui-angular/chat/README.md)
+
 - `IgxGrid`, `IgxTreeGrid`, `IgxHierarchicalGrid`
     - Added PDF export functionality to grid components. Grids can now be exported to PDF format alongside the existing Excel and CSV export options.
-    
+
         The new `IgxPdfExporterService` follows the same pattern as Excel and CSV exporters:
 
         ```ts
@@ -60,9 +51,16 @@ All notable changes for each version of this project will be documented in this
         - **Landscape orientation** by default (suitable for wide grids)
         - **Internationalization** support for all 19 supported languages
         - Respects all grid export options (ignoreFiltering, ignoreSorting, ignoreColumnsVisibility, etc.)
-        
+
 ### Breaking Changes
 
+- `IgxButton`
+    - The following shadow-related parameters were removed from the `outlined-button-theme` and `flat-button-theme`:
+        - `resting-shadow`
+        - `hover-shadow`
+        - `focus-shadow`
+        - `active-shadow`
+
 #### Dependency Injection Refactor
 - All internal DI now uses the `inject()` API across `igniteui-angular` (no more constructor DI in library code).
 - If you extend our components/services or call their constructors directly, remove DI params and switch to `inject()` (e.g., `protected foo = inject(FooService);`).

projects/igniteui-angular/chat/README.md

@@ -0,0 +1,93 @@
+
+# IgxChat
+
+**IgxChat** is a component that provides a chat interface, wrapping the **IgcChat** web component.
+
+A walkthrough of how to get started can be found [here](https://www.infragistics.com/products/ignite-ui-angular/angular/components/chat)
+
+# Usage
+
+```html
+<igx-chat
+    [messages]="messages"
+    [draftMessage]="draft"
+    [options]="chatOptions"
+    [templates]="chatTemplates"
+    (messageCreated)="onMessageCreated($event)">
+</igx-chat>
+```
+
+# API Summary
+The following tables summarize the **igx-chat** inputs, outputs and directives.
+
+### Inputs
+The following inputs are available in the **igx-chat** component:
+
+| Name | Type | Description |
+| :--- | :--- | :--- |
+| `messages` | `IgcChatMessage[]` | Array of chat messages to display |
+| `draftMessage` | `{ text: string; attachments?: IgcChatMessageAttachment[] } \| undefined` | Draft message with text and optional attachments |
+| `options` | `IgxChatOptions` | Configuration options for the chat component |
+| `templates` | `IgxChatTemplates` | Custom templates for rendering chat elements |
+
+### Outputs
+The following outputs are available in the **igx-chat** component:
+
+| Name | Description | Parameters |
+| :--- | :--- | :--- |
+| `messageCreated` | Emitted when a new message is created | `IgcChatMessage` |
+| `messageReact` | Emitted when a user reacts to a message | `IgcChatMessageReaction` |
+| `attachmentClick` | Emitted when an attachment is clicked | `IgcChatMessageAttachment` |
+| `attachmentDrag` | Emitted when attachment drag starts | `void` |
+| `attachmentDrop` | Emitted when attachment is dropped | `void` |
+| `typingChange` | Emitted when typing indicator state changes | `boolean` |
+| `inputFocus` | Emitted when the input receives focus | `void` |
+| `inputBlur` | Emitted when the input loses focus | `void` |
+| `inputChange` | Emitted when the input value changes | `string` |
+
+### Directives
+The following directives are available for type checking in templates:
+
+| Name | Selector | Description |
+| :--- | :--- | :--- |
+| `IgxChatMessageContextDirective` | `[igxChatMessageContext]` | Provides type information for chat message template contexts |
+| `IgxChatAttachmentContextDirective` | `[igxChatAttachmentContext]` | Provides type information for chat attachment template contexts |
+| `IgxChatInputContextDirective` | `[igxChatInputContext]` | Provides type information for chat input template contexts |
+
+# Chat Extras
+
+The **chat-extras** module provides additional utilities for enhancing chat functionality.
+
+## MarkdownPipe
+
+The `MarkdownPipe` transforms markdown text into HTML, allowing you to render formatted messages in the chat.
+
+### Usage
+
+```typescript
+import { MarkdownPipe } from 'igniteui-angular/chat-extras';
+
+@Component({
+    standalone: true,
+    imports: [IgxChatComponent, MarkdownPipe, AsyncPipe],
+    template: `
+        <igx-chat [messages]="messages" [templates]="templates">
+            <ng-template #renderer igxChatMessageContext let-message>
+                <div [innerHTML]="message.text | fromMarkdown | async"></div>
+            </ng-template>
+        </igx-chat>
+    `
+})
+```
+
+### Supported Markdown Features
+
+The pipe supports common markdown syntax including:
+- **Bold** text (`**text**`)
+- *Italic* text (`*text*`)
+- Headings (`# H1`, `## H2`, etc.)
+- Lists (ordered and unordered)
+- Links (`[text](url)`)
+- Code blocks and inline code
+- Blockquotes
+- And more...