refactor(viz-platform): extract skills and slim commands

Extract shared knowledge from 10 commands into 7 reusable skills:
- mcp-tools-reference.md: All viz-platform MCP tool signatures
- theming-system.md: Theme tokens, CSS variables, color palettes
- accessibility-rules.md: WCAG contrast, color-blind safe palettes
- dmc-components.md: DMC categories, validation, common props
- responsive-design.md: Breakpoints, mobile-first, grid config
- chart-types.md: Plotly chart types, export formats, resolution
- layout-templates.md: Dashboard templates, filter types

All commands now reference skills via "Skills to Load" section.
Commands reduced from 1396 lines total to 427 lines (69% reduction).

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

plugins/viz-platform/commands/chart-export.md

@@ -4,19 +4,19 @@ description: Export a Plotly chart to PNG, SVG, or PDF format
 
 # Export Chart
 
+## Skills to Load
+- skills/mcp-tools-reference.md
+- skills/chart-types.md
+
 ## Visual Output
 
-When executing this command, display the plugin header:
-
 ```
-┌──────────────────────────────────────────────────────────────────┐
-│  🎨 VIZ-PLATFORM · Chart Export                                   │
-└──────────────────────────────────────────────────────────────────┘
++------------------------------------------------------------------+
+|  VIZ-PLATFORM - Chart Export                                     |
++------------------------------------------------------------------+
 ```
 
-Then proceed with the export.
-
-Export a Plotly chart to static image formats for sharing, embedding, or printing.
+Export a Plotly chart to static image formats.
 
 ## Usage
 
@@ -26,101 +26,17 @@ Export a Plotly chart to static image formats for sharing, embedding, or printin
 
 ## Arguments
 
-- `format` (required): Output format - one of: png, svg, pdf
-
-## Examples
-
-```
-/chart-export png
-/chart-export svg
-/chart-export pdf
-```
+- `format` (required): png, svg, or pdf
 
 ## Tool Mapping
 
-This command uses the `chart_export` MCP tool:
-
 ```python
-chart_export(
-    figure=figure_json,           # Plotly figure JSON from chart_create
-    format="png",                 # Output format: png, svg, pdf
-    width=1200,                   # Optional: image width in pixels
-    height=800,                   # Optional: image height in pixels
-    scale=2,                      # Optional: resolution scale factor
-    output_path=None              # Optional: save to file path
-)
+chart_export(figure=figure_json, format="png", width=1200, height=800, scale=2)
 ```
 
-## Workflow
-
-1. **User invokes**: `/chart-export png`
-2. **Agent asks**: Which chart to export? (if multiple charts in context)
-3. **Agent asks**: Image dimensions? (optional, uses chart defaults)
-4. **Agent exports**: Chart with `chart_export` tool
-5. **Agent returns**: Base64 image data or file path
-
-## Output Formats
-
-| Format | Best For | File Size |
-|--------|----------|-----------|
-| `png` | Web, presentations, general use | Medium |
-| `svg` | Scalable graphics, editing | Small |
-| `pdf` | Print, documents, archival | Large |
-
-## Resolution Options
-
-### Width & Height
-Specify exact pixel dimensions:
-```python
-chart_export(figure, format="png", width=1920, height=1080)
-```
-
-### Scale Factor
-Increase resolution for high-DPI displays:
-```python
-chart_export(figure, format="png", scale=3)  # 3x resolution
-```
-
-Common scale values:
-- `1` - Standard resolution (72 DPI)
-- `2` - Retina/HiDPI (144 DPI)
-- `3` - Print quality (216 DPI)
-- `4` - High-quality print (288 DPI)
-
-## Output Options
-
-### Return as Base64
-Default behavior - returns base64-encoded image data:
-```python
-result = chart_export(figure, format="png")
-# result["image_data"] contains base64 string
-```
-
-### Save to File
-Specify output path to save directly:
-```python
-chart_export(figure, format="png", output_path="/path/to/chart.png")
-# result["file_path"] contains the saved path
-```
-
-## Requirements
-
-This tool requires the `kaleido` package for rendering:
-```bash
-pip install kaleido
-```
-
-Kaleido is a cross-platform library that renders Plotly figures without a browser.
-
-## Error Handling
-
-Common issues:
-- **Kaleido not installed**: Install with `pip install kaleido`
-- **Invalid figure**: Ensure figure is valid Plotly JSON
-- **Permission denied**: Check write permissions for output path
+Requires `kaleido` package: `pip install kaleido`
 
 ## Related Commands
 
 - `/chart {type}` - Create a chart
 - `/theme {name}` - Apply theme before export
-- `/dashboard` - Create layout containing charts