refactor: rename command files for namespace consistency

BREAKING CHANGE: All generic command names now prefixed with plugin namespace.
See CHANGELOG.md v7.0.0 for complete rename map.

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

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

@@ -0,0 +1,41 @@
+---
+description: Create a Plotly chart with theme integration
+---
+
+# Create Chart
+
+## Skills to Load
+- skills/mcp-tools-reference.md
+- skills/chart-types.md
+
+## Visual Output
+
+```
++------------------------------------------------------------------+
+|  VIZ-PLATFORM - Chart Builder                                    |
++------------------------------------------------------------------+
+```
+
+Create a Plotly chart with automatic theme token application.
+
+## Usage
+
+```
+/chart {type}
+```
+
+## Arguments
+
+- `type` (required): line, bar, scatter, pie, area, histogram, box, heatmap, sunburst, treemap
+
+## Tool Mapping
+
+```python
+chart_create(chart_type="line", data_ref="df", x="date", y="value", theme=None)
+```
+
+## Related Commands
+
+- `/chart-export {format}` - Export chart to image
+- `/theme {name}` - Apply theme to charts
+- `/dashboard` - Create layout with charts