[codex] Remove unused legacy shell tools (#22246)

## Why

Recent session history showed no active use of the raw `shell`,
`local_shell`, or `container.exec` execution surfaces. Keeping those
handlers/specs wired into core leaves duplicate shell execution paths
alongside the supported `shell_command` and unified exec tools.

## What changed

- Removed the raw `shell` handler/spec and its `ShellToolCallParams`
protocol helper.
- Removed the legacy `local_shell` and `container.exec` handler/spec
plumbing while preserving persisted-history compatibility for old
response items.
- Normalized model/config `default` and `local` shell selections to
`shell_command`.
- Pruned tests that exercised removed raw-shell/local-shell/apply-patch
variants and kept coverage on `shell_command`, unified exec, and
freeform `apply_patch`.

## Verification

- `git diff --check`
- `cargo test -p codex-protocol`
- `cargo test -p codex-tools`
- `cargo test -p codex-core tools::handlers::shell`
- `cargo test -p codex-core tools::spec`
- `cargo test -p codex-core tools::router`
- `cargo test -p codex-core
active_call_preserves_triggering_command_context`
- `cargo test -p codex-core guardian_tests`
- `cargo test -p codex-core --test all shell_serialization`
- `cargo test -p codex-core --test all apply_patch_cli`
- `cargo test -p codex-core --test all shell_command_`
- `cargo test -p codex-core --test all local_shell`
- `cargo test -p codex-core --test all otel::`
- `cargo test -p codex-core --test all hooks::`
- `just fix -p codex-core`
- `just fix -p codex-tools`

codex-rs/core/src/stream_events_utils.rs

@@ -289,34 +289,6 @@ pub(crate) async fn handle_output_item_done(
 
             output.last_agent_message = last_agent_message;
         }
-        // Guardrail: the model issued a LocalShellCall without an id; surface the error back into history.
-        Err(FunctionCallError::MissingLocalShellCallId) => {
-            let msg = "LocalShellCall without call_id or id";
-            ctx.turn_context
-                .session_telemetry
-                .log_tool_failed("local_shell", msg);
-            tracing::error!(msg);
-
-            let response = ResponseInputItem::FunctionCallOutput {
-                call_id: String::new(),
-                output: FunctionCallOutputPayload {
-                    body: FunctionCallOutputBody::Text(msg.to_string()),
-                    ..Default::default()
-                },
-            };
-            record_completed_response_item(ctx.sess.as_ref(), ctx.turn_context.as_ref(), &item)
-                .await;
-            if let Some(response_item) = response_input_to_response_item(&response) {
-                ctx.sess
-                    .record_conversation_items(
-                        &ctx.turn_context,
-                        std::slice::from_ref(&response_item),
-                    )
-                    .await;
-            }
-
-            output.needs_follow_up = true;
-        }
         // The tool request should be answered directly (or was denied); push that response into the transcript.
         Err(FunctionCallError::RespondToModel(message)) => {
             let response = ResponseInputItem::FunctionCallOutput {