[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/linux-sandbox/tests/suite/landlock.rs

@@ -1,6 +1,6 @@
 #![cfg(target_os = "linux")]
 #![allow(clippy::unwrap_used)]
-use codex_core::config::types::ShellEnvironmentPolicy;
+use codex_config::types::ShellEnvironmentPolicy;
 use codex_core::error::CodexErr;
 use codex_core::error::Result;
 use codex_core::error::SandboxErr;

codex-rs/linux-sandbox/tests/suite/managed_proxy.rs

@@ -1,7 +1,7 @@
 #![cfg(target_os = "linux")]
 #![allow(clippy::unwrap_used)]
 
-use codex_core::config::types::ShellEnvironmentPolicy;
+use codex_config::types::ShellEnvironmentPolicy;
 use codex_core::exec_env::create_env;
 use codex_protocol::protocol::SandboxPolicy;
 use pretty_assertions::assert_eq;