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/theme-new.md

@@ -4,18 +4,18 @@ description: Create a new custom theme with design tokens
 
 # Create New Theme
 
+## Skills to Load
+- skills/mcp-tools-reference.md
+- skills/theming-system.md
+
 ## Visual Output
 
-When executing this command, display the plugin header:
-
 ```
-┌──────────────────────────────────────────────────────────────────┐
-│  🎨 VIZ-PLATFORM · New Theme                                      │
-└──────────────────────────────────────────────────────────────────┘
++------------------------------------------------------------------+
+|  VIZ-PLATFORM - New Theme                                        |
++------------------------------------------------------------------+
 ```
 
-Then proceed with the theme creation.
-
 Create a new custom theme with specified design tokens.
 
 ## Usage
@@ -28,99 +28,11 @@ Create a new custom theme with specified design tokens.
 
 - `name` (required): Name for the new theme
 
-## Examples
-
-```
-/theme-new corporate
-/theme-new dark-blue
-/theme-new brand-theme
-```
-
 ## Tool Mapping
 
-This command uses the `theme_create` MCP tool:
-
 ```python
-theme_create(
-    name="corporate",
-    primary_color="indigo",
-    color_scheme="light",
-    font_family="Inter, sans-serif",
-    heading_font_family=None,        # Optional: separate heading font
-    border_radius="md",              # xs, sm, md, lg, xl
-    spacing_scale=1.0,               # Multiplier for spacing
-    colors=None                      # Optional: custom color palette
-)
-```
-
-## Workflow
-
-1. **User invokes**: `/theme-new corporate`
-2. **Agent asks**: Primary color preference?
-3. **Agent asks**: Light or dark color scheme?
-4. **Agent asks**: Font family preference?
-5. **Agent creates**: Theme with `theme_create`
-6. **Agent validates**: Theme with `theme_validate`
-7. **Agent activates**: New theme is ready to use
-
-## Theme Properties
-
-### Colors
-- `primary_color`: Main accent color (blue, indigo, violet, etc.)
-- `color_scheme`: "light" or "dark"
-- `colors`: Custom color palette override
-
-### Typography
-- `font_family`: Body text font
-- `heading_font_family`: Optional heading font
-
-### Spacing
-- `border_radius`: Component corner rounding
-- `spacing_scale`: Multiply default spacing values
-
-## Mantine Color Palette
-
-Available primary colors:
-- blue, cyan, teal, green, lime
-- yellow, orange, red, pink, grape
-- violet, indigo, gray, dark
-
-## Custom Color Example
-
-```python
-theme_create(
-    name="brand",
-    primary_color="custom",
-    colors={
-        "custom": [
-            "#e6f7ff",  # 0 - lightest
-            "#bae7ff",  # 1
-            "#91d5ff",  # 2
-            "#69c0ff",  # 3
-            "#40a9ff",  # 4
-            "#1890ff",  # 5 - primary
-            "#096dd9",  # 6
-            "#0050b3",  # 7
-            "#003a8c",  # 8
-            "#002766"   # 9 - darkest
-        ]
-    }
-)
-```
-
-## Extending Themes
-
-To create a theme based on another:
-
-```python
-theme_extend(
-    base_theme="dark",
-    name="dark-corporate",
-    overrides={
-        "primary_color": "indigo",
-        "font_family": "Roboto, sans-serif"
-    }
-)
+theme_create(name="corporate", primary_color="indigo", color_scheme="light", font_family="Inter")
+theme_validate(theme_name="corporate")
 ```
 
 ## Related Commands