Add plugin development side quest, restructure side quests for multi-part courses

.editorconfig

@@ -15,6 +15,10 @@ indent_size = 2
 [*.{py,md}]
 indent_style = unset
 
+# Makefiles require tabs
+[Makefile]
+indent_style = tab
+
 # ignore nf-core generated files
 [side-quests/solutions/nf-core/**]
 charset = unset

.gitignore

@@ -12,6 +12,9 @@ transcript-index
 __pycache__
 *.pyc
 
+# Gradle build artifacts
+.gradle/
+
 # Build outputs
 site/
 site_build/

.pre-commit-config.yaml

@@ -12,15 +12,16 @@ repos:
     hooks:
       - id: editorconfig-checker
         alias: ec
+        exclude: hello-plugins/.*/nf-greeting/(COPYING|gradlew)$
 
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v5.0.0
     hooks:
       - id: trailing-whitespace
         exclude_types:
           - svg
-        exclude: ^hello-nf-core/solutions/core-hello-.*/
+        exclude: (^hello-nf-core/solutions/core-hello-.*/)|(hello-plugins/.*/COPYING$)
       - id: end-of-file-fixer
         exclude_types:
           - svg
-        exclude: ^hello-nf-core/solutions/core-hello-.*/
+        exclude: (^hello-nf-core/solutions/core-hello-.*/)|(hello-plugins/.*/COPYING$)

.prettierignore

@@ -15,3 +15,6 @@ side-quests/solutions/nf-core/**/*.yml
 
 # Ignore nf-core pipeline solutions (generated by nf-core tools, not hand-authored)
 hello-nf-core/solutions/core-hello-*/**
+
+# Ignore auto-generated license files in plugin solutions
+hello-plugins/**/COPYING

docs/en/docs/envsetup/02_local.md

@@ -18,7 +18,7 @@ Our training courses have a few additional requirements.
 In total, you will need to have the following software installed:
 
 - Bash or equivalent shell
-- [Java 11 (or later, up to 21)](https://www.oracle.com/technetwork/java/javase/downloads/index.html)
+- [Java 21 or later](https://www.oracle.com/technetwork/java/javase/downloads/index.html) (Java 11+ is sufficient for running Nextflow, but the [plugin development](../hello_plugins/index.md) course requires Java 21)
 - [Git](https://git-scm.com/)
 - [Docker](https://docs.docker.com/get-docker/)
 - [Conda](https://conda.io/) 4.5 (or later)

docs/en/docs/hello_plugins/00_orientation.md

@@ -0,0 +1,115 @@
+# Orientation
+
+This page will help you set up your environment and navigate through the training.
+
+!!! warning "Development sections are advanced"
+
+    Using existing plugins (Part 1) is straightforward and valuable for all Nextflow users.
+
+    Parts 2-6 cover building your own plugins, which many Nextflow developers may never need to do.
+    However, creating a plugin can be a good way to share reusable functions across pipelines or within a team.
+    These lessons involve Groovy code, build tools, and concepts that may be new if your background is in scripting or data analysis rather than software engineering.
+    No prior Java or Groovy experience is required; the lessons explain these concepts as they come up.
+
+    If the development sections feel challenging, focus on Part 1 and return to the rest when you have a specific plugin idea in mind.
+
+---
+
+## 1. Open the training environment
+
+If you haven't yet done so, make sure to open the training environment as described in the [Environment Setup](../envsetup/index.md).
+
+[![Open in GitHub Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/nextflow-io/training?quickstart=1&ref=master)
+
+---
+
+## 2. Verify Java installation
+
+Plugin development (Parts 2-6) requires Java 21 or later, which is included in the training environment.
+Verify it's available:
+
+```bash
+java -version
+```
+
+You should see Java 21 or later.
+
+??? info "What are Java, Groovy, and Gradle?"
+
+    If these terms are unfamiliar, here's a quick primer:
+
+    **Java** is a widely-used programming language.
+    Nextflow itself is built with Java, and plugins must be compatible with the Java runtime.
+
+    **Groovy** is a programming language that runs on Java and is designed to be more concise and flexible.
+    Nextflow's DSL is based on Groovy, which is why Nextflow syntax looks the way it does.
+    Plugin code is typically written in Groovy.
+
+    **Gradle** is a build tool that compiles code, runs tests, and packages software.
+    You don't need to understand Gradle deeply; we'll use simple commands like `./gradlew build`.
+
+    You don't need to be an expert in any of these.
+    The plugin template handles most of the complexity for you.
+
+---
+
+## 3. Move into the project directory
+
+```bash
+cd hello-plugins
+```
+
+---
+
+## 4. Review the materials
+
+```bash
+tree -L 1
+```
+
+```console
+.
+├── greetings.csv
+├── greetings_schema.json
+├── greet.nf
+├── hello.nf
+├── nextflow.config
+└── solutions/
+```
+
+The directory contains two pipeline files: `hello.nf` for the Part 1 exercises (using existing plugins) and `greet.nf` for Parts 2-6 (building your own plugin).
+
+---
+
+## 5. What we'll cover
+
+This training is organized into two tracks:
+
+**Using plugins (Part 1):**
+
+- Discover, install, configure, and use existing plugins like `nf-hello`
+
+**Developing plugins (Parts 2-6):**
+
+- Create a plugin project with `nf-greeting`
+- Implement custom functions
+- Build, test, and install locally
+- Monitor workflow events for custom logging or notifications
+- Make plugins configurable
+- Distribute your plugin
+
+---
+
+## 6. Readiness checklist
+
+- [ ] My codespace is running
+- [ ] Java is installed (for plugin development parts)
+- [ ] I'm in the `hello-plugins` directory
+
+---
+
+### What's next?
+
+In the next section, you'll start using an existing plugin in a workflow.
+
+[Continue to Part 1 :material-arrow-right:](01_plugin_basics.md){ .md-button .md-button--primary }