Add missing light/dark image variants for workshop assets in steps 01–14

[Copilot]

This updates the first workshop segment so image assets consistently provide theme-specific variants. Any workshop/images asset in the 01–14 range that only existed as a single SVG now has both -light and -dark counterparts.

• Scope

  • Targets image assets used in early workshop content (01 through 14).
  • Standardizes asset availability for dark/light rendering without changing workshop copy or image references.

• Asset updates

  • Added -light and -dark variants for all previously single-version SVGs in that range, including:
    • 01-preflight-success
    • 01-terminal-basics-annotated
    • 02a-fork-repo
    • 02b-terminal-command-annotated
    • 02b-terminal-success-* (missing subset)
    • 03-actions-tab
    • 07-workflow-committed
    • 07a-workflow-file-anatomy
    • 07b-agent-compile-loop
    • 12-workflow-run-log
    • 13-schedule-badge

• Resulting convention

  • For each base asset X.svg, the set is now expected to include:

    X-light.svg
    X-dark.svg
    

[pelikhan]

@copilot review the dark theme images and make sure they are DARK THEMED!

[Copilot]

@copilot review the dark theme images and make sure they are DARK THEMED!

Updated in ce5f614: I audited all newly added -dark assets and converted the dark variants to a GitHub dark-theme palette so they are no longer light-theme duplicates.