[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/tui/src/notifications/mod.rs

@@ -5,7 +5,7 @@ use std::env;
 use std::io;
 
 use bel::BelBackend;
-use codex_core::config::types::NotificationMethod;
+use codex_config::types::NotificationMethod;
 use osc9::Osc9Backend;
 
 #[derive(Debug)]
@@ -74,7 +74,7 @@ fn supports_osc9() -> bool {
 #[cfg(test)]
 mod tests {
     use super::detect_backend;
-    use codex_core::config::types::NotificationMethod;
+    use codex_config::types::NotificationMethod;
     use serial_test::serial;
     use std::ffi::OsString;