Add copilot instructions

Author: akurtakov

.github/copilot-instructions.md

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+# Eclipse Linux Tools – Copilot Instructions
+
+## Build and Test
+
+```bash
+mvn clean verify
+```
+
+Tests require a virtual display (Xvnc) because they run in a UI harness. On CI this is handled automatically. Locally, use `Xvfb` or skip UI tests with `-DskipTests`.
+
+## Architecture
+
+This is a **multi-module Eclipse/OSGi plugin project** built with **Maven + Tycho**. It is not a standard Java application — every plugin is an OSGi bundle declared in `META-INF/MANIFEST.MF`, not just a Maven artifact.
+
+### Top-level modules
+
+| Directory     | Content |
+|---------------|---------|
+| `containers/` | Docker integration (UI, core, Dockerfile LS, tests) |
+| `rpm/`        | RPM `.spec` editor, rpmlint integration, RPM core |
+| `profiling/`  | Shared profiling launch framework, data viewers, remote/SSH proxy |
+| `gcov/`       | GCov coverage analysis |
+| `gprof/`      | GProf call-graph profiling |
+| `valgrind/`   | Valgrind heap analysis |
+| `perf/`       | Linux `perf` call profiling |
+| `systemtap/`  | SystemTap IDE integration |
+| `changelog/`  | ChangeLog editor/formatter |
+| `libhover/`   | C library hover documentation |
+| `lttng/`      | LTTng tracing support |
+| `vagrant/`    | Vagrant VM integration |
+| `releng/`     | Update sites, target platform, release engineering |
+
+Each top-level directory is itself a Maven aggregator `pom.xml` listing its plugins, features, docs, and test plugins as `<module>` entries.
+
+### Target platform
+
+All dependencies are defined in:
+```
+releng/org.eclipse.linuxtools.target/linuxtools-latest.target
+```
+This file is auto-updated daily against the latest Eclipse Orbit and SimRel repositories. Do **not** hand-edit dependency versions for Eclipse platform dependencies in `pom.xml` — add them to the `.target` file instead.
+
+### Plugin naming conventions
+
+- **Core logic:** `org.eclipse.linuxtools.<component>.core`
+- **UI:** `org.eclipse.linuxtools.<component>.ui`
+- **Tests:** `org.eclipse.linuxtools.<component>.*.tests` — packaged as `eclipse-test-plugin`
+- **Features:** `org.eclipse.linuxtools.<component>-feature` — packaged as `eclipse-feature`
+- **Internal (non-API) packages:** `org.eclipse.linuxtools.internal.<component>.*`
+
+Public API lives in `org.eclipse.linuxtools.<component>.*`; implementation details live under `org.eclipse.linuxtools.internal.<component>.*`.
+
+### Two separate update sites
+
+The `releng/` module produces two p2 repositories:
+- `org.eclipse.linuxtools.releng-site` — all tools except containers
+- `org.eclipse.linuxtools.docker-site` — Docker/container tools only
+
+## Key Conventions
+
+### Java and OSGi
+- **Java 21** is required (`Bundle-RequiredExecutionEnvironment: JavaSE-21` in all manifests).
+- Plugin dependencies are declared in `META-INF/MANIFEST.MF` via `Require-Bundle` or `Import-Package`, not Maven `<dependency>`. Tycho resolves the classpath from these.
+- Each plugin `pom.xml` contains almost nothing — just the parent reference and `<packaging>eclipse-plugin</packaging>`.
+
+### Tests
+- Tests use **JUnit 5 (Jupiter)**: `org.junit.jupiter.api.Assertions`, `@Test`, `@BeforeEach`, `@AfterEach`.
+- Test plugins run inside a live Eclipse workbench (`useUIHarness=true`, `useUIThread=true`). Tests can use Eclipse workspace and UI APIs directly.
+
+### Copyright header
+Every Java file must start with:
+```java
+/*******************************************************************************
+ * Copyright (c) <year> <Author> and others.
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    <Author> - initial API and implementation
+ *******************************************************************************/
+```
+
+### Commits
+Non-committers must add a `Signed-off-by` trailer and have a signed [Eclipse Contributor Agreement (ECA)](http://www.eclipse.org/legal/ECA.php) on file.
+
+### Release branches
+Stable branches are named `stable-<x>` (e.g., `stable-8.5`). The `master` branch always targets the next SNAPSHOT version.