[prompts] Make validation automatic instead of optional

Changes all style-creation prompts to automatically validate instead of
asking the user. Validation is fast (offline only), catches issues early,
and provides immediate feedback without friction.

Rationale:
- All validation tools are offline (no API calls, no cost)
- Fast execution (milliseconds)
- Follows development tool patterns (ESLint, TypeScript, tests)
- Results are informational - users can ignore warnings for prototypes
- Better to show issues immediately than discover them later

Updated prompts:
- create-and-preview-style: Step 5 now validates automatically
- build-custom-map: Step 5 now validates automatically
- design-data-driven-style: Step 8 now validates automatically
- setup-mapbox-project: Validates before presenting final summary

Changes:
- Removed user question "Would you like to validate?"
- Added automatic validation step after style creation
- Validation results included in final summary
- Note added that warnings can be ignored for prototypes

Benefits:
- Catches expression errors before runtime
- Ensures WCAG accessibility compliance by default
- Identifies optimization opportunities immediately
- Especially valuable for AI-generated styles (build-custom-map)
- Data-driven styles get complex expression validation

Example flow:
1. Create style ✓
2. Generate preview ✓
3. Automatically validate ✓ (new - runs without asking)
4. Present: Preview URL + Validation report

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: mattpodwysocki

src/prompts/BuildCustomMapPrompt.ts

@@ -89,22 +89,27 @@ Follow these steps to create and preview the styled map:
     instructionText += `\n   - Set zoom level to: ${previewZoom}
    - The preview will use an existing public token automatically
 
-5. **Present results**
+5. **Validate the style**
+   - Automatically run validation using the prepare-style-for-production prompt
+   - Pass the style ID from step 3 as the style_id_or_json parameter
+   - This checks:
+     * Expression syntax (especially important for AI-generated styles)
+     * Color contrast for accessibility (WCAG AA)
+     * Style optimization opportunities
+   - Validation is fast (offline processing only)
+
+6. **Present complete results**
    - Show the user:
      * A summary of the theme and customizations applied
      * The style ID for future reference
      * The preview URL to view the map
+     * Validation results summary:
+       - ✅ Issues found or "Style is production-ready"
+       - Expression validation status (critical for generated styles)
+       - Accessibility compliance (WCAG AA)
+       - Optimization recommendations
      * Suggestions for further customization if desired
-
-6. **Validate the style (recommended for production)**
-   - After presenting the preview, ask the user:
-     * "Would you like to validate this style for production readiness? This will check expressions, accessibility, and optimize the style."
-   - If yes:
-     * Use the prepare-style-for-production prompt
-     * Pass the style ID from step 3 as the style_id_or_json parameter
-   - If no:
-     * Note: "You can validate later by running the prepare-style-for-production prompt when needed"
-   - For experimental or demo maps, validation can be skipped
+   - Note: Validation warnings can be ignored for experimental maps
 
 **Theme interpretation tips:**
 - "Dark cyberpunk": Dark backgrounds, neon colors (cyan, magenta, purple), high contrast
@@ -118,10 +123,11 @@ Follow these steps to create and preview the styled map:
 
     instructionText += `\n\n**Important notes:**
 - The style_builder_tool is powered by AI and may need refinement
+- Validation runs automatically to catch any issues in generated expressions
 - You can iterate on the style by making additional calls to style_builder_tool
 - If the initial result doesn't match expectations, try refining the theme description
 - Consider the map's use case when choosing zoom levels and preview locations
-- For production deployment, always validate styles to ensure quality and accessibility`;
+- For experimental maps, validation warnings can be addressed later`;
 
     return [
       {

src/prompts/CreateAndPreviewStylePrompt.ts

@@ -112,27 +112,33 @@ Follow these steps carefully:
     instructionText += `\n   - Set zoom level to: ${previewZoom}
    - The tool will automatically use the public token you created/found earlier
 
-5. **Present results**
+5. **Validate the style**
+   - Automatically run validation using the prepare-style-for-production prompt
+   - Pass the style ID from step 3 as the style_id_or_json parameter
+   - This checks:
+     * Expression syntax and correctness
+     * Color contrast for accessibility (WCAG AA)
+     * Style optimization opportunities
+   - Validation is fast (offline processing only)
+
+6. **Present complete results**
    - Show the user:
      * The created style ID
      * The preview URL (they can click to open in browser)
+     * Validation results summary:
+       - ✅ Issues found or "Style is production-ready"
+       - Expression validation status
+       - Accessibility compliance (WCAG AA)
+       - Optimization recommendations
      * Instructions to share or embed the preview
-
-6. **Validate the style (recommended for production)**
-   - After presenting the preview, ask the user:
-     * "Would you like to validate this style for production readiness? This will check expressions, accessibility, and optimize the style."
-   - If yes:
-     * Use the prepare-style-for-production prompt
-     * Pass the style ID from step 3 as the style_id_or_json parameter
-   - If no:
-     * Note: "You can validate later by running the prepare-style-for-production prompt when needed"
-   - For quick prototypes or demos, validation can be skipped
+   - Note: Validation warnings can be ignored for quick prototypes
 
 **Important notes:**
 - The preview_style_tool will automatically fetch and use an available public token
 - Make sure the style is created successfully before generating the preview
+- Validation runs automatically to catch issues early (offline, fast)
 - If any step fails, provide clear error messages and suggest fixes
-- For production deployment, always validate styles to catch issues early`;
+- For quick prototypes, validation warnings can be addressed later`;
 
     return [
       {

src/prompts/DesignDataDrivenStylePrompt.ts

@@ -395,31 +395,32 @@ Show property values as labels:
 - Use red/green combinations (colorblind-unfriendly)
 - Forget to handle null/undefined property values
 
-## Step 8: Validate the Style (Recommended for Production)
+## Step 8: Validate the Style
 
-After creating your data-driven style:
+After creating your data-driven style, automatically run validation:
 
-1. **Ask the user about validation:**
-   - "Would you like to validate this data-driven style for production readiness? This will check expression syntax, accessibility, and optimize the style."
-   - Data-driven styles use complex expressions that benefit from validation
-
-2. **If yes, validate:**
+1. **Run validation:**
    - Use the prepare-style-for-production prompt
    - Pass the style ID as the style_id_or_json parameter
+   - Data-driven styles use complex expressions that benefit from validation
    - This checks:
      * Expression syntax and type correctness
-     * Color contrast for accessibility (WCAG AA/AAA)
+     * Color contrast for accessibility (WCAG AA)
      * Overall style optimization
+   - Validation is fast (offline processing only)
+
+2. **Present validation results:**
+   - Include validation summary with the preview:
+     * ✅ Issues found or "Style is production-ready"
+     * Expression validation status (critical for data-driven styles)
+     * Accessibility compliance (WCAG AA)
+     * Optimization recommendations
    - This ensures your expressions work correctly with real data
 
-3. **If no:**
-   - Note: "You can validate later using prepare-style-for-production when ready for production"
-
-4. **When validation is especially important:**
-   - ✅ Production maps with real user data
-   - ✅ Styles with complex nested expressions
-   - ✅ Maps requiring accessibility compliance
-   - ⚠️ Quick prototypes can skip validation initially
+3. **Note for users:**
+   - Validation runs automatically to catch issues early
+   - For quick prototypes, warnings can be addressed later
+   - Complex nested expressions especially benefit from validation
 
 ## Step 9: Documentation
 

src/prompts/SetupMapboxProjectPrompt.ts

@@ -254,14 +254,27 @@ Type: ${projectType}
 
     instructionText += `
 
-📋 **Optional: Validate the Style for Production**
-
-Before deploying to production, consider validating the created style:
-- Ask the user: "Would you like to validate this style for production readiness? This will check expressions, accessibility, and optimize the style."
-- If yes, use the prepare-style-for-production prompt with the style ID created above
-- If no, note that validation is recommended before production deployment
-
-The setup is now complete! The user can start building their map application.`;
+📋 **Validate the Style**
+
+Automatically validate the created style:
+- Use the prepare-style-for-production prompt with the style ID created above
+- This checks:
+  * Expression syntax and correctness
+  * Color contrast for accessibility (WCAG AA)
+  * Style optimization opportunities
+- Validation is fast (offline processing only)
+- Include validation results in the final summary
+
+🎉 **Setup Complete!**
+
+Present the complete setup summary:
+- All tokens created with proper security restrictions
+- Map style created and validated
+- Preview URL for testing
+- Validation results (any issues or "✅ Production-ready")
+- Next steps for integration
+
+The user can now start building their map application with confidence that their setup follows best practices.`;
 
     return [
       {