core tests: build user turns from permission profiles (#20011)

## Summary
- Add `turn_permission_fields()` so tests that construct `Op::UserTurn`
directly can provide a canonical `PermissionProfile` while still filling
the required legacy `sandbox_policy` compatibility field.
- Migrate direct user-turn construction in core integration tests from
`SandboxPolicy::DangerFullAccess` to `PermissionProfile::Disabled`.
- Continue reducing direct `SandboxPolicy` usage in
`codex-rs/core/tests`, from 41 files after #20010 to 32 files in this
PR.

## Testing
- `cargo check -p codex-core --tests`
- `just fmt`
- `just fix -p core_test_support`
- `just fix -p codex-core`

codex-rs/core/tests/suite/skills.rs

@@ -9,9 +9,9 @@ use codex_exec_server::ExecServerRuntimePaths;
 use codex_exec_server::ExecutorFileSystem;
 use codex_login::CodexAuth;
 use codex_models_manager::collaboration_mode_presets::CollaborationModesConfig;
+use codex_protocol::models::PermissionProfile;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::Op;
-use codex_protocol::protocol::SandboxPolicy;
 use codex_protocol::protocol::SessionSource;
 use codex_protocol::user_input::UserInput;
 use codex_utils_absolute_path::AbsolutePathBuf;
@@ -24,6 +24,7 @@ use core_test_support::responses::sse;
 use core_test_support::responses::start_mock_server;
 use core_test_support::skip_if_no_network;
 use core_test_support::test_codex::test_codex;
+use core_test_support::test_codex::turn_permission_fields;
 use pretty_assertions::assert_eq;
 use std::fs;
 use std::path::Path;
@@ -97,6 +98,8 @@ async fn user_turn_includes_skill_instructions() -> Result<()> {
     .await;
 
     let session_model = test.session_configured.model.clone();
+    let (sandbox_policy, permission_profile) =
+        turn_permission_fields(PermissionProfile::Disabled, test.config.cwd.as_path());
     test.codex
         .submit(Op::UserTurn {
             environments: None,
@@ -114,8 +117,8 @@ async fn user_turn_includes_skill_instructions() -> Result<()> {
             cwd: test.config.cwd.to_path_buf(),
             approval_policy: AskForApproval::Never,
             approvals_reviewer: None,
-            sandbox_policy: SandboxPolicy::DangerFullAccess,
-            permission_profile: None,
+            sandbox_policy,
+            permission_profile,
             model: session_model,
             effort: None,
             summary: None,