Add contractors by residence endpoint and Bruno API collection

- Add GET /contractors/by-residence/:residence_id/ endpoint
- Create comprehensive Bruno API collection (89 endpoints)
- Collection covers all API endpoints with Local and Dev environments

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

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

bruno-collections/casera-api/Authentication/Register.bru

@@ -0,0 +1,19 @@
+meta {
+  name: Register
+  type: http
+  seq: 2
+}
+
+post {
+  url: {{api_url}}/auth/register/
+  body: json
+  auth: none
+}
+
+body:json {
+  {
+    "username": "newuser",
+    "email": "newuser@example.com",
+    "password": "securepassword123"
+  }
+}