Add external import sources, work history, screening fields and Phase 1 docs

- New ExternalImportSource and ExternalWorkHistoryEntry models, controller and migrations
- Screening fields on external profile imports
- Admin and provider profile views, routes and workflow tests updated
- Phase 1 validation, route inventory, gap report template and roadmap docs
- Add the Google Sheets work-order parser tool (tools/google-sheets-wo-parser)

tools/google-sheets-wo-parser/tests/fixtures.cjs

@@ -0,0 +1,23 @@
+module.exports = {
+  fieldNationNew: {
+    id: 'field-nation-message-001',
+    from: 'Field Nation <notifications@fieldnation.example>',
+    subject: 'New Work Order: Network troubleshooting',
+    date: new Date('2026-08-02T14:00:00Z'),
+    plainBody: `Field Nation\nNew work order available\nWork Order #19660234\nTitle: Network troubleshooting\nBuyer: Example Field Services\nLocation: Raleigh, NC 27609\nService Date: Monday, Aug 3 @ 8:00 AM\nPay Total: $225.00\nPay Type: Hourly Rate\nEstimated 3 hours\nView work order: https://app.fieldnation.com/workorders/19660234`
+  },
+  workMarketRouted: {
+    id: 'workmarket-message-002',
+    from: 'WorkMarket <no-reply@workmarket.example>',
+    subject: 'You have been routed a work order',
+    date: new Date('2026-08-02T14:05:00Z'),
+    plainBody: `WorkMarket\nYou have been routed a work order.\nWork Order ID: WM-884221\nJob Title: POS terminal swap\nCompany: Example Buyer LLC\nService Location: Durham, NC 27713\nScheduled Time: Tuesday, Aug 4 @ 10:00 AM\nTotal Pay: $180.00\nFixed Rate\nOpen assignment: https://www.workmarket.com/work-orders/WM-884221`
+  },
+  unknown: {
+    id: 'unknown-message-003',
+    from: 'Some Sender <example@example.com>',
+    subject: 'Hello',
+    date: new Date('2026-08-02T14:10:00Z'),
+    plainBody: 'This is not a work-order notification.'
+  }
+};