New task (zenflow 738246ea)

In the Pairing Simulator page, I am getting the error:

**Error:**Unexpected token '<', "<!DOCTYPE "... is not valid JSON

Fid and fix the bug

.zenflow/tasks/new-task-7382/investigation.md

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+# Bug Investigation & Implementation Report - Task 7382
+
+## Bug Summary
+The Pairing Simulator was failing with the error: `Unexpected token '<', "<!DOCTYPE "... is not valid JSON`. This was caused by a mismatch between the frontend's expected API endpoint and the server's actual routes, leading to a 404 HTML response instead of JSON.
+
+## Root Cause Analysis
+1. **Endpoint Mismatch**: The frontend called `POST /api/pedigree/coi`, but the server only implemented `POST /api/pedigree/trial-pairing`.
+2. **Property Naming**: The frontend expected `common_ancestors` (snake_case), while the server returned `commonAncestors` (camelCase).
+3. **Data Structure**: The frontend expected `common_ancestors` to be an array of strings, while the server returned an array of objects.
+4. **COI Scaling**: The server returned COI as a percentage (e.g., 25.00), while the frontend functions (`coiColor`, `coiLabel`) expected decimals (e.g., 0.25).
+
+## Affected Components
+- `client/src/pages/PairingSimulator.jsx`
+- `server/routes/pedigree.js`
+
+## Proposed & Implemented Solution
+1. **Server Fix**: Modified `calculateCOI` in `server/routes/pedigree.js` to return the raw decimal value for `coefficient`.
+2. **Frontend Fix**: Updated `PairingSimulator.jsx` to:
+   - Use the documented `/api/pedigree/trial-pairing` endpoint.
+   - Use the `commonAncestors` property from the response.
+   - Access the `.name` property when mapping over the common ancestors list.
+   - The COI display logic `(result.coi * 100).toFixed(2)` now works correctly with the decimal value from the server.
+
+## Verification Results
+- Manual code analysis confirms that the frontend and backend now share a consistent API contract.
+- The COI thresholds and color coding in the frontend now correctly interpret the values provided by the server.