Auto-enable first theme when no active theme is set on plugin launch or pull

[Copilot]

Problem

When users launch the plugin or pull variables from Figma without any stored active theme information, no theme is automatically enabled. This requires users to manually select a theme even when themes are available, creating unnecessary friction in the workflow.

Solution

This PR implements automatic activation of the first available theme when:

• No active theme is currently set (activeTheme is empty {})
• Themes are available in the plugin

The auto-enable behavior occurs in two key scenarios:

1. On plugin startup - When loading token data via setTokenData
2. When pulling variables - When pulling variables from Figma via setThemesFromVariables

Implementation Details

The solution modifies two key reducers to detect when no active theme is set and automatically enable the first available theme:

setThemesFromVariables (when pulling variables)

// Auto-enable the first theme if no active theme is set and themes are available
const hasActiveTheme = Object.keys(state.activeTheme).length > 0;
const allThemes = [...state.themes, ...newThemes];

if (!hasActiveTheme && allThemes.length > 0) {
  const firstTheme = allThemes[0];
  const groupKey = firstTheme.group || INTERNAL_THEMES_NO_GROUP;
  newActiveTheme = { [groupKey]: firstTheme.id };
  
  // Update usedTokenSet based on the first theme's selectedTokenSets
  // ... (enables the appropriate token sets)
}

setTokenData (on plugin startup)

Similar logic is applied when loading token data during plugin initialization, ensuring the first theme is auto-enabled if no active theme exists.

Both functions update not only activeTheme but also usedTokenSet based on the theme's selectedTokenSets, ensuring that the correct token sets are properly enabled when the theme is activated.

Theme Group Handling

• If a theme has a group property, it's used as the key in activeTheme
• If a theme has no group, the INTERNAL_THEMES_NO_GROUP constant is used
• This matches the existing theme management behavior throughout the plugin

Testing

Added comprehensive test suite covering:

• ✅ Auto-enabling first theme with groups
• ✅ Auto-enabling first theme without groups (using INTERNAL_THEMES_NO_GROUP)
• ✅ Preserving existing active theme when one is already set
• ✅ Not auto-enabling when no themes are available

All existing tests continue to pass, confirming backward compatibility.

Changeset

Created a patch-level changeset as required by repository guidelines.

Original prompt

When we dont have information on what Themes are active or not, make it so the first theme option is always enabled when launching the plugin or pulling

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[changeset-bot]

🦋 Changeset detected

Latest commit: 8b98e1d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@tokens-studio/figma-plugin	Patch

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