feat(plugins): implement Sprint 4 commands (#241-#258)

Sprint 4 - Plugin Commands implementation adding 18 new user-facing
commands across 8 plugins as part of V5.2.0 Plugin Enhancements.

**projman:**
- #241: /sprint-diagram - Mermaid visualization of sprint issues

**pr-review:**
- #242: Confidence threshold config (PR_REVIEW_CONFIDENCE_THRESHOLD)
- #243: /pr-diff - Formatted diff with inline review comments

**data-platform:**
- #244: /data-quality - DataFrame quality checks (nulls, duplicates, outliers)
- #245: /lineage-viz - dbt lineage as Mermaid diagrams
- #246: /dbt-test - Formatted dbt test runner

**viz-platform:**
- #247: /chart-export - Export charts to PNG/SVG/PDF via kaleido
- #248: /accessibility-check - Color blind validation (WCAG contrast)
- #249: /breakpoints - Responsive layout configuration

**contract-validator:**
- #250: /dependency-graph - Plugin dependency visualization

**doc-guardian:**
- #251: /changelog-gen - Generate changelog from conventional commits
- #252: /doc-coverage - Documentation coverage metrics
- #253: /stale-docs - Flag outdated documentation

**claude-config-maintainer:**
- #254: /config-diff - Track CLAUDE.md changes over time
- #255: /config-lint - 31 lint rules for CLAUDE.md best practices

**cmdb-assistant:**
- #256: /cmdb-topology - Infrastructure topology diagrams
- #257: /change-audit - NetBox audit trail queries
- #258: /ip-conflicts - Detect IP conflicts and overlaps

Closes #241, #242, #243, #244, #245, #246, #247, #248, #249,
#250, #251, #252, #253, #254, #255, #256, #257, #258

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

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

@@ -0,0 +1,114 @@
+---
+description: Export a Plotly chart to PNG, SVG, or PDF format
+---
+
+# Export Chart
+
+Export a Plotly chart to static image formats for sharing, embedding, or printing.
+
+## Usage
+
+```
+/chart-export {format}
+```
+
+## Arguments
+
+- `format` (required): Output format - one of: png, svg, pdf
+
+## Examples
+
+```
+/chart-export png
+/chart-export svg
+/chart-export 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
+)
+```
+
+## 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
+
+## Related Commands
+
+- `/chart {type}` - Create a chart
+- `/theme {name}` - Apply theme before export
+- `/dashboard` - Create layout containing charts