[codex] Remove codex-core config type shim (#16529)

## Why

This finishes the config-type move out of `codex-core` by removing the
temporary compatibility shim in `codex_core::config::types`. Callers now
depend on `codex-config` directly, which keeps these config model types
owned by the config crate instead of re-expanding `codex-core` as a
transitive API surface.

## What Changed

- Removed the `codex-rs/core/src/config/types.rs` re-export shim and the
`core::config::ApprovalsReviewer` re-export.
- Updated `codex-core`, `codex-cli`, `codex-tui`, `codex-app-server`,
`codex-mcp-server`, and `codex-linux-sandbox` call sites to import
`codex_config::types` directly.
- Added explicit `codex-config` dependencies to downstream crates that
previously relied on the `codex-core` re-export.
- Regenerated `codex-rs/core/config.schema.json` after updating the
config docs path reference.

codex-rs/cli/tests/mcp_add_remove.rs

@@ -1,8 +1,8 @@
 use std::path::Path;
 
 use anyhow::Result;
+use codex_config::types::McpServerTransportConfig;
 use codex_core::config::load_global_mcp_servers;
-use codex_core::config::types::McpServerTransportConfig;
 use predicates::str::contains;
 use pretty_assertions::assert_eq;
 use tempfile::TempDir;

codex-rs/cli/tests/mcp_list.rs

@@ -1,9 +1,9 @@
 use std::path::Path;
 
 use anyhow::Result;
+use codex_config::types::McpServerTransportConfig;
 use codex_core::config::edit::ConfigEditsBuilder;
 use codex_core::config::load_global_mcp_servers;
-use codex_core::config::types::McpServerTransportConfig;
 use predicates::prelude::PredicateBooleanExt;
 use predicates::str::contains;
 use pretty_assertions::assert_eq;