Add theme-aware SVG pairs for 3 workshop images (#2020)

Author: github-actions[bot]

workshop/00-welcome.md

@@ -9,7 +9,11 @@
 
 By the end of this workshop, a real AI agent will create an issue with a summary of the activity in your repository over the latest 24h, every day, without you writing shell-script workflow code.
 
-![Sample daily repository status report generated by the finished workflow](images/00-daily-repo-status-output.svg)
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="images/00-daily-repo-status-output-dark.svg">
+  <source media="(prefers-color-scheme: light)" srcset="images/00-daily-repo-status-output-light.svg">
+  <img alt="Sample daily repository status report generated by the finished workflow" src="images/00-daily-repo-status-output-light.svg">
+</picture>
 
 You'll build a **[GitHub Agentic Workflow](https://github.github.com/gh-aw/introduction/overview/)**:
 > A GitHub Action that uses AI to inspect your repository, decide what matters, and publish a useful status report on a schedule — practical enough to adapt for real teams.

workshop/04-github-actions-intro.md

@@ -74,7 +74,11 @@ Traditional workflows execute a fixed script path. [Agentic workflows](https://g
 
 The diagram below shows how the five key parts fit together in every workflow file.
 
-![GitHub Actions workflow anatomy: trigger, job, runner, steps, and actions shown as nested layers](images/04-actions-anatomy.svg)
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="images/04-actions-anatomy-dark.svg">
+  <source media="(prefers-color-scheme: light)" srcset="images/04-actions-anatomy-light.svg">
+  <img alt="GitHub Actions workflow anatomy: trigger, job, runner, steps, and actions shown as nested layers" src="images/04-actions-anatomy-light.svg">
+</picture>
 
 Before reading on, label each highlighted part of the workflow below with its type:
 `trigger`, `job`, `runner`, `step`, or `action`.

workshop/07-your-first-workflow.md

@@ -8,7 +8,11 @@ _Writing your first workflow is the moment theory becomes practice — let's mak
 
 You'll use Copilot to create `.github/workflows/daily-report-status.md` — a scheduled workflow that also supports manual dispatch. You'll configure it with [`permissions`](https://github.github.com/gh-aw/reference/permissions/), [`safe-outputs`](https://github.github.com/gh-aw/reference/safe-outputs/), and a task brief, then compile it to produce `daily-report-status.lock.yml`, the file [GitHub Actions](https://github.github.com/gh-aw/guides/github-actions-primer/) runs.
 
-![Diagram showing how daily-report-status.md is compiled by gh aw compile into daily-report-status.lock.yml which GitHub Actions then executes](images/07-compile-flow.svg)
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="images/07-compile-flow-dark.svg">
+  <source media="(prefers-color-scheme: light)" srcset="images/07-compile-flow-light.svg">
+  <img alt="Diagram showing how daily-report-status.md is compiled by gh aw compile into daily-report-status.lock.yml which GitHub Actions then executes" src="images/07-compile-flow-light.svg">
+</picture>
 
 ## 📋 Before You Start