Remove the gRPC code-mode enabled tool limit (#38615)

## What changed

Stop rejecting code-mode execute requests solely because `enabled_tools`
contains more than 1,024 definitions. Continue validating each tool definition
while converting the request.

GitOrigin-RevId: da83b61c5f659e6aa221ed663821edcdfc29d3f1

codex-rs/code-mode-host/src/grpc/conversions.rs

@@ -29,12 +29,6 @@ pub(super) fn session_limits(
 
 pub(super) fn execute_request(request: proto::ExecuteRequest) -> Result<ExecuteRequest, Status> {
     validation::identifier(&request.tool_call_id, "tool call ID")?;
-    if request.enabled_tools.len() > validation::MAX_TOOL_DEFINITIONS {
-        return Err(Status::invalid_argument(format!(
-            "code-mode execution exceeds {} enabled tools",
-            validation::MAX_TOOL_DEFINITIONS
-        )));
-    }
     Ok(ExecuteRequest {
         tool_call_id: request.tool_call_id,
         source: request.source,

codex-rs/code-mode-host/src/grpc/validation.rs

@@ -5,7 +5,6 @@ use uuid::Uuid;
 pub(super) use codex_code_mode_protocol::grpc::MAX_IDENTIFIER_BYTES;
 pub(super) use codex_code_mode_protocol::grpc::MAX_TOOL_ERROR_BYTES;
 pub(super) const MAX_TOOL_FILTERS: usize = 64;
-pub(super) const MAX_TOOL_DEFINITIONS: usize = 1_024;
 
 pub(super) fn identifier(value: &str, field: &str) -> Result<(), Status> {
     if value.is_empty() {