[workshop-ui-screenshots] Add theme-aware SVG screenshots for 3 workshop images

[github-actions]

Summary

This PR migrates three single-theme workshop images to GitHub-native theme-aware <picture> blocks with paired light and dark SVG variants.

Generated light/dark pairs

Stem	Light	Dark	Repairs broken?	Migrates existing?
07a-workflow-dispatch-trigger	workshop/images/07a-workflow-dispatch-trigger-light.svg	workshop/images/07a-workflow-dispatch-trigger-dark.svg	No	✅ Yes
13-pr-reviewer-comment	workshop/images/13-pr-reviewer-comment-light.svg	workshop/images/13-pr-reviewer-comment-dark.svg	No	✅ Yes
16-data-source-run	workshop/images/16-data-source-run-light.svg	workshop/images/16-data-source-run-dark.svg	No	✅ Yes

Markdown files updated

• workshop/07a-your-first-workflow-terminal.md — workflow_dispatch trigger diagram
• workshop/14b-pr-reviewer-workflow.md — PR auto-reviewer comment screenshot
• workshop/16-connect-data-source.md — Actions run with fetch-issues step

Each plain ![alt](path) reference was replaced with the GitHub theme-aware <picture> pattern (dark <source> first, light <source> second, light fallback <img>).

QA

All six SVGs were validated with Playwright (Chromium) in both colorScheme: light and colorScheme: dark. Each <picture> block selected the correct -light.svg / -dark.svg variant and rendered with non-zero bounding boxes.

Note: These are AI-generated conceptual illustrations derived from the original single-theme SVGs with a dark-palette color transformation applied. Maintainers should replace them with real screenshots when available.

Warning

Firewall blocked 5 domains

The following domains were blocked by the firewall during workflow execution:

• accounts.google.com
• awmgmcpg
• clients2.google.com
• storage.googleapis.com
• www.google.com

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "accounts.google.com"
    - "awmgmcpg"
    - "clients2.google.com"
    - "storage.googleapis.com"
    - "www.google.com"

See Network Configuration for more information.

Generated by 🖼️ Workshop UI Screenshot Generator · 75.2 AIC · ⌖ 8.06 AIC · ⊞ 6.7K · ◷

• expires on Jul 26, 2026, 3:37 AM UTC