feat(viz-platform): complete Sprint 1 - plugin structure and tests

Sprint 1 - viz-platform Plugin completed (13/13 issues):
- Commands: 7 files (initial-setup, chart, dashboard, theme, theme-new, theme-css, component)
- Agents: 3 files (theme-setup, layout-builder, component-check)
- Documentation: README.md, claude-md-integration.md
- Tests: 94 tests passing (68-99% coverage)
- CHANGELOG updated with completion status

Closes: #178, #179, #180, #181, #182

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

plugins/viz-platform/commands/theme-new.md

@@ -0,0 +1,117 @@
+---
+description: Create a new custom theme with design tokens
+---
+
+# Create New Theme
+
+Create a new custom theme with specified design tokens.
+
+## Usage
+
+```
+/theme-new {name}
+```
+
+## Arguments
+
+- `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"
+    }
+)
+```
+
+## Related Commands
+
+- `/theme {name}` - Apply a theme
+- `/theme-css {name}` - Export theme as CSS