[ACS-11173] Initial set of rules for Copilot review (#11683)

* [ACS-11173] Initial set of rules for Copilot review

* [ACS-11173] CR fix

.github/instructions/html.instructions.md

@@ -0,0 +1,23 @@
+---
+applyTo: "**/*.html"
+---
+
+# HTML Development Standards
+
+* Simple Templates: Keep templates as simple as possible, avoiding complex logic directly in the template. Delegate complex logic to the component's TypeScript code.
+* Native Control Flow: Use the new built-in control flow syntax (`@if`, `@for`, `@switch`) instead of the older structural directives (`*ngIf`, `*ngFor`, `*ngSwitch`).
+* NgOptimizedImage: Use `NgOptimizedImage` for all static images to automatically optimize image loading and performance.
+* Async Pipe: Use the `async` pipe to handle observables in templates. This automatically subscribes and unsubscribes, preventing memory leaks.
+* Prefer pipes over functions in templates for performance reasons, as pipes are only re-evaluated when their inputs change.
+
+## Accessibility Standards
+
+* Add `alt` text to all images
+* Label form inputs with `<mat-label>` or `aria-label`
+* Ensure interactive elements have accessible names
+* Add `role`, `aria-labelledby`, and `aria-describedby` when semantic HTML isn't sufficient
+* All interactive elements must be keyboard accessible
+* Ensure 4.5:1 contrast ratio for normal text, 3:1 for large text
+* Use `aria-live="polite"` for status updates
+* Watch out for misused/non-semantic elements (e.g., <div> instead of <section>)
+* Avoid broken heading hierarchy (e.g., h1 → h3 without h2)