feat(*): updating changelog for 21.2.0

Author: kdinev

CHANGELOG.md

@@ -20,6 +20,18 @@ All notable changes for each version of this project will be documented in this
 
 - `IgxOverlayService`
     - **Deprecation** - The `outlet` property in `OverlaySettings`, `IgxOverlayOutletDirective`, and `igxToggleOutlet` input on `IgxToggleActionDirective` are deprecated and will be removed in a future version. As overlay service now integrates the HTML Popover API and prefers rendering content in place / in the top layer, significantly reducing the need for outlet containers, new code should rely on the default in-place / top-layer rendering behavior instead of custom outlet containers.
+    
+- **AI-Assisted Development - Copilot Skill: Generate from Image Design**
+    - Added a new `igniteui-angular-generate-from-image-design` Copilot Skill that teaches AI coding assistants/agents (e.g., GitHub Copilot, Cursor, Windsurf, Claude, JetBrains AI, etc.) how to implement Angular application views directly from design images (screenshots, mockups, wireframes).
+    - The skill provides a structured workflow covering image analysis, component discovery via MCP tools (`list_components`, `get_doc`), theme generation (`create_palette`, `create_theme`, `create_component_theme`), layout implementation, and visual refinement (`set_size`, `set_spacing`, `set_roundness`).
+    - Includes reference files:
+        - **Component Mapping** - Maps common UI patterns (dashboards, charts, forms, navigation, data display, gauges) to the most appropriate Ignite UI for Angular component with key properties and decision rules.
+        - **Gotchas** - Documents known pitfalls, component-specific constraints, and corrective patterns to help AI agents avoid common implementation mistakes.
+
+- **AI-Assisted Development - Copilot Skills improvements**
+    - `igniteui-angular-grids` skill - Added a new `sizing.md` reference covering grid and column width/height inputs, percentage and auto sizing modes, column sizing (`minWidth`, `maxWidth`, `*` star-sizing, auto-fit), and cell spacing/density control.
+    - `igniteui-angular-components` skill - Corrected Financial Chart (`IgxFinancialChartComponent`) documentation: updated `chartType` enum values to `Auto`, `Candle`, `Line`, `Bar`, `Column` to match the actual `FinancialChartType` API.
+    - `igniteui-angular-theming` skill - Minor cleanup to remove stale internal contributing reference.
 
 ## 21.1.3