chore: Clean up verbosity config (#3056)

## Summary
It appears that #2108 hit a merge conflict with #2355 - I failed to
notice the path difference when re-reviewing the former. This PR
rectifies that, and consolidates it into the protocol package, in line
with our philosophy of specifying types in one place.

## Testing
- [x] Adds config test for model_verbosity

codex-rs/core/src/client_common.rs

@@ -1,4 +1,3 @@
-use crate::config_types::Verbosity as VerbosityConfig;
 use crate::error::Result;
 use crate::model_family::ModelFamily;
 use crate::openai_tools::OpenAiTool;
@@ -6,6 +5,7 @@ use crate::protocol::TokenUsage;
 use codex_apply_patch::APPLY_PATCH_TOOL_INSTRUCTIONS;
 use codex_protocol::config_types::ReasoningEffort as ReasoningEffortConfig;
 use codex_protocol::config_types::ReasoningSummary as ReasoningSummaryConfig;
+use codex_protocol::config_types::Verbosity as VerbosityConfig;
 use codex_protocol::models::ContentItem;
 use codex_protocol::models::ResponseItem;
 use futures::Stream;