Add scenario-modeler-server example

Demo MCP App for SaaS financial planning with:
- Interactive sliders for MRR, growth, churn, margin, and costs
- 12-month projection charts (MRR, Gross Profit, Net Profit)
- 5 pre-built scenario templates (Bootstrapped, VC Rocketship, etc.)
- Template comparison overlay for strategy analysis
- Light/dark theme support

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

examples/scenario-modeler-server/README.md

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+# Example: SaaS Scenario Modeler
+
+A React-based demo MCP App that lets users adjust SaaS business parameters and see real-time 12-month projections of revenue, costs, and profitability with comparison against pre-built scenario templates.
+
+## Features
+
+- **Interactive Parameters**: 5 sliders for Starting MRR, Growth Rate, Churn Rate, Gross Margin, and Fixed Costs
+- **12-Month Projections**: Line chart showing MRR, Gross Profit, and Net Profit over time
+- **Scenario Templates**: 5 pre-built business strategies (Bootstrapped, VC Rocketship, Cash Cow, Turnaround, Efficient Growth)
+- **Template Comparison**: Overlay dashed lines to compare your scenario against any template
+- **Summary Metrics**: Key metrics including Ending MRR, Total Revenue, Total Profit, and break-even month
+- **Theme Support**: Adapts to light/dark mode preferences
+
+## Running
+
+1. Install dependencies:
+
+   ```bash
+   npm install
+   ```
+
+2. Build and start the server:
+
+   ```bash
+   npm start
+   ```
+
+   The server will listen on `http://localhost:3001/mcp`.
+
+3. View using the [`basic-host`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-host) example or another MCP Apps-compatible host.
+
+## Architecture
+
+### Server (`server.ts`)
+
+Exposes a single `get-scenario-data` tool that returns:
+
+- 5 pre-built scenario templates with parameters, projections, and summaries
+- Default input values for the sliders
+- Optionally computes custom projections when `customInputs` are provided
+
+The tool is linked to a UI resource via `_meta[RESOURCE_URI_META_KEY]`.
+
+### App (`src/`)
+
+- Built with React for reactive slider updates and derived state management
+- Uses Chart.js for the line chart visualization
+- All projection calculations run client-side for instant slider feedback
+- Components: `SliderRow`, `MetricCard`, `ProjectionChart`
+- Template comparison shown as dashed overlay lines on the chart