test(redis): isolated tests for the type-specific editors

[ZhuchkaTriplesix]

Summary

Adds test/features/redis/redis_type_editors_test.dart: isolated widget tests for the editors extracted in #1034 (RedisStringEditor, RedisHashEditor, RedisListEditor, RedisSetEditor, RedisZsetEditor), driven by plain callbacks without a connection.

• String: value and Save, typing updates the parent-owned controller, read-only hides Save and locks the field, a binary value is shown as hex / base64 without Save.
• Hash: fields and values, HSET trims the field name but keeps the value and clears the inputs, an empty field name is ignored, delete reports the field, read-only hides the add bar and delete icons, empty state and footer.
• List: items with indexes, RPUSH (sent as typed, empty ignored), editing sends LSET with the value the item had (concurrency guard input), cancel / unchanged text sends nothing, delete reports index and item, binary items get a badge and no edit icon, read-only, empty state.
• Set: SADD trims and ignores blanks, delete, read-only, empty state.
• Sorted set: scores (whole numbers without decimals), ZADD parses the score and trims the member, an empty member or a non-numeric score is ignored, delete, read-only.

Coverage of the rest of #1040

Most of the listed suites already exist and are not duplicated here: Mongo view modes (mongo_documents_view_modes_test), aggregation (mongo_aggregation_stage_test, mongo_aggregation_workspace_test), indexes (mongo_indexes_view_test, mongo_index_info_test), MQL console (mongo_query_workspace_test, mql_parser_test), Redis key tree (redis_key_tree_engine_test) and CLI (redis_cli_workspace_test).

Still open: the Mongo collection tree suite (#1023). The tree widgets are private parts of ConnectionsPanel and need a Mongo connection fake, so that is a separate, larger piece.

Written without running locally; CI is the first run.

Refs #1040