Enhance strict typing and improve job initialization in FA and Inkbunny domains

- Refactored job classes in the FA domain to enforce strict typing with Sorbet, including the addition of type signatures in `FavsJob` and `Base` classes.
- Updated initialization methods to accept variable arguments and ensure proper type handling.
- Improved error handling in `ApiSearchPageProcessor` to gracefully manage null values for `last_file_update_datetime`.
- Added a new fixture for testing scenarios where `last_file_update_datetime` is null, enhancing test coverage.

These changes aim to improve type safety, maintainability, and robustness of the job processing logic.

test/fixtures/files/domain/inkbunny/job/api_search_null_last_file_update.json

@@ -0,0 +1,116 @@
+{
+  "sid": "9B5BPQqTZ,Mj-nYbL2tuIPoO,b",
+  "results_count_all": "564",
+  "results_count_thispage": 100,
+  "pages_count": 1,
+  "page": 1,
+  "user_location": "",
+  "rid": "dc55754e57",
+  "rid_ttl": "15 minutes",
+  "search_params": [
+    {
+      "param_name": "field_join_type",
+      "param_value": "or"
+    },
+    {
+      "param_name": "text",
+      "param_value": ""
+    },
+    {
+      "param_name": "string_join_type",
+      "param_value": "and"
+    },
+    {
+      "param_name": "keywords",
+      "param_value": "no"
+    },
+    {
+      "param_name": "keyword_id",
+      "param_value": false
+    },
+    {
+      "param_name": "title",
+      "param_value": "no"
+    },
+    {
+      "param_name": "description",
+      "param_value": "no"
+    },
+    {
+      "param_name": "md5",
+      "param_value": "no"
+    },
+    {
+      "param_name": "username",
+      "param_value": ""
+    },
+    {
+      "param_name": "user_id",
+      "param_value": "16532"
+    },
+    {
+      "param_name": "favs_user_id",
+      "param_value": ""
+    },
+    {
+      "param_name": "unread_submissions",
+      "param_value": "no"
+    },
+    {
+      "param_name": "type",
+      "param_value": ""
+    },
+    {
+      "param_name": "pool_id",
+      "param_value": ""
+    },
+    {
+      "param_name": "orderby",
+      "param_value": "create_datetime"
+    },
+    {
+      "param_name": "dayslimit",
+      "param_value": ""
+    },
+    {
+      "param_name": "random",
+      "param_value": "no"
+    },
+    {
+      "param_name": "scraps",
+      "param_value": "both"
+    },
+    {
+      "param_name": "count_limit",
+      "param_value": 18000
+    }
+  ],
+  "submissions": [
+    {
+      "submission_id": "2855990",
+      "hidden": "f",
+      "username": "Darkwitt",
+      "user_id": "16532",
+      "create_datetime": "2022-11-23 11:19:51.482781+00",
+      "create_datetime_usertime": "23 Nov 2022 12:19 CET",
+      "last_file_update_datetime": null,
+      "last_file_update_datetime_usertime": "01 Jan 1970 01:00 CET",
+      "file_name": null,
+      "title": "New Submission",
+      "deleted": "f",
+      "public": "t",
+      "mimetype": null,
+      "pagecount": "0",
+      "rating_id": "2",
+      "rating_name": "Adult",
+      "file_url_full": false,
+      "file_url_screen": false,
+      "file_url_preview": false,
+      "submission_type_id": "1",
+      "type_name": "Picture/Pinup",
+      "friends_only": "f",
+      "guest_block": "f",
+      "scraps": "f"
+    }
+  ]
+}