feat: add TypeScript implementation guidelines and Copilot setup workflow

Author: mahata

.github/copilot-instructions.md

@@ -8,14 +8,8 @@ Please use `pnpm` as your package manager. However, try to avoid introducing unn
 
 ## Implementation
 
-Write code in `TypeScript` and avoid using the `any` type as much as possible. Maintain code formatting according to `Biome` rules.
-
-Avoid code comments. Instead, consider using descriptive variable names to make it clear what the code is doing on its own.
-
-Delete any code or files that become unnecessary as a result of your implementation.
+Write code in `TypeScript`. Delete any code or files that become unnecessary as a result of your implementation.
 
 ## Testing
 
 Follow the TDD principles as Kent Beck writes: Red-Green-Refactor is the way to go. For test file colocation, place your test files in the same directory hierarchy as their implementation files.
-
-Use `Vitest` as a testing framework.

.github/workflows/copilot-setup-steps.yml

@@ -0,0 +1,29 @@
+name: "Copilot Setup Steps"
+
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+  copilot-setup-steps:
+    runs-on: ubuntu-24.04
+
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Check this conf is respected
+        run: |
+          if [ ! -f .github/workflows/copilot-setup-steps.yml ]; then
+            echo "Copilot setup steps file not found."
+            exit 1
+          fi
+          echo "Copilot setup steps file exists."

.github/workflows/instructions/typescript.instructions.md

@@ -0,0 +1,16 @@
+---
+applyTo: "**/*.ts,**/*.tsx"
+---
+
+## Implementation
+
+- Follow functional programming principles where possible
+- Use interfaces for data structures and type definitions
+- Prefer immutable data (`const`, `readonly`)
+- Use optional chaining (`?.`) and nullish coalescing (`??`) operators
+- Avoid `any` type as much as possible
+- Avoid code comments in favor of descriptive variable names
+
+## Testing
+
+Use `Vitest` as a testing framework.