Improve copilot instructions and setup

.github/copilot-instructions.md

@@ -5,8 +5,8 @@
 This repository contains the core Eclipse Platform components that form the basis for the Eclipse IDE. It is a **large-scale Java/OSGi project** (~120MB, 5,600+ Java files across 38 Maven modules) using **Maven/Tycho** for building Eclipse RCP bundles and features.
 
 **Key Technologies:**
-- Language: Java (JDK 17+, targets JDK 21 in CI)
-- Build: Maven 3.9+ with Eclipse Tycho (OSGi/RCP build tooling)
+- Language: Java (JDK 21)
+- Build: Maven 3.9.11 with Eclipse Tycho (OSGi/RCP build tooling)
 - Architecture: OSGi bundles organized as Eclipse plugins
 - Testing: JUnit with Tycho Surefire plugin
 
@@ -22,25 +22,10 @@ This repository contains the core Eclipse Platform components that form the basi
 
 ## Critical Build Information
 
-**⚠️ IMPORTANT: This repository CANNOT be built in isolation.** It depends on a parent POM (`eclipse-platform-parent`) from the [eclipse.platform.releng.aggregator](https://github.com/eclipse-platform/eclipse.platform.releng.aggregator) repository. 
-
-### Individual Bundle Builds
-
-Individual bundles CAN be built using the pre-configured profile if you have network access to Eclipse repositories:
-
-```bash
-cd <bundle-directory>  # e.g., runtime/bundles/org.eclipse.core.runtime
-mvn clean verify -Pbuild-individual-bundles
-```
-
 The `-Pbuild-individual-bundles` profile (configured in `.mvn/maven.config`) enables the bundle to fetch the parent POM from https://repo.eclipse.org/content/repositories/eclipse/.
 
 **Note:** If network access to Eclipse repositories is blocked, individual bundle builds will fail. In such environments, code exploration and analysis can still be performed, but build verification is not possible.
 
-### Full Platform Build
-
-For full platform builds, use the aggregator repository which includes this repo as a Git submodule. The CI workflows in this repository delegate to workflows in the aggregator repository.
-
 ### Build Profiles Used in CI
 
 The Jenkinsfile shows the complete build command:

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

@@ -0,0 +1,32 @@
+name: "Copilot Setup Steps"
+
+# Automatically run the setup steps when they are changed to allow for easy validation, and
+# allow manual testing through the repository's "Actions" tab
+on:
+  workflow_dispatch:
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+    # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+          cache: 'maven'
+
+      - name: Set up Maven 3.9.11
+        uses: stCarolas/setup-maven@v5
+        with:
+          maven-version: '3.9.11'
+