feat: filter professionals by city and proximity

- findAllActive now accepts city, lat, lng params
- City filter: case-insensitive contains on users.city
- Proximity sort: Haversine within city before services/score ranking
- Controller exposes ?city=&lat=&lng= query params

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/professionals/professionals.controller.ts

@@ -16,7 +16,10 @@ export class ProfessionalsController {
   @Get()
   findAllActive(@Req() req) {
     const search = req.query.search as string | undefined;
-    return this.pros.findAllActive(search);
+    const city = req.query.city as string | undefined;
+    const lat = req.query.lat ? parseFloat(req.query.lat as string) : undefined;
+    const lng = req.query.lng ? parseFloat(req.query.lng as string) : undefined;
+    return this.pros.findAllActive(search, city, lat, lng);
   }
 
   @Get('pending')