remove temporary ownership re-exports (#16626)

Stacked on #16508.

This removes the temporary `codex-core` / `codex-login` re-export shims
from the ownership split and rewrites callsites to import directly from
`codex-model-provider-info`, `codex-models-manager`, `codex-api`,
`codex-protocol`, `codex-feedback`, and `codex-response-debug-context`.

No behavior change intended; this is the mechanical import cleanup layer
split out from the ownership move.

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/app-server/tests/common/Cargo.toml

@@ -18,6 +18,7 @@ codex-app-server-protocol = { workspace = true }
 codex-core = { workspace = true }
 codex-features = { workspace = true }
 codex-login = { workspace = true }
+codex-models-manager = { workspace = true }
 codex-protocol = { workspace = true }
 codex-utils-cargo-bin = { workspace = true }
 serde = { workspace = true }

codex-rs/app-server/tests/common/models_cache.rs

@@ -1,6 +1,7 @@
 use chrono::DateTime;
 use chrono::Utc;
 use codex_core::test_support::all_model_presets;
+use codex_models_manager::client_version_to_whole;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::ModelInfo;
@@ -84,7 +85,7 @@ pub fn write_models_cache_with_models(
     let cache_path = codex_home.join("models_cache.json");
     // DateTime<Utc> serializes to RFC3339 format by default with serde
     let fetched_at: DateTime<Utc> = Utc::now();
-    let client_version = codex_core::models_manager::client_version_to_whole();
+    let client_version = client_version_to_whole();
     let cache = json!({
         "fetched_at": fetched_at,
         "etag": null,