fix(cli): show filenames in operation list

[r266-tech]

Summary

• carry the optional operation filename field through the CLI's operation list model
• show Filename: in pretty hindsight operations list output when the API provides it
• set refresh_cron: None on existing mental-model trigger requests so the CLI continues compiling against the current generated Rust client schema

Context

#2420 made file-upload operations expose the original filename on the API response so operators can identify pending or failed uploads. The CLI still converted the response into its local Operation type without that field, so pretty output only showed opaque operation/document IDs.

While verifying the CLI tests, the current generated Rust client also required the newer nullable refresh_cron field on MentalModelTriggerInput; adding None preserves the existing CLI behavior and keeps the focused tests compiling.

Tests

• cargo test --manifest-path hindsight-cli/Cargo.toml --locked operation::tests
• cargo test --manifest-path hindsight-cli/Cargo.toml --locked api::tests::test_operation_deserialize
• cargo test --manifest-path hindsight-cli/Cargo.toml --locked api::tests::test_operation_deserialize_with_error
• cargo test --manifest-path hindsight-cli/Cargo.toml --locked api::tests::test_operations_response_deserialize