app-server: expose thread permission profiles (#18278)

## Why

The `PermissionProfile` migration needs app-server clients to see the
same constrained permission model that core is using at runtime. Before
this PR, thread lifecycle responses only exposed the legacy
`SandboxPolicy` shape, so clients still had to infer active permissions
from sandbox fields. That makes downstream resume, fork, and override
flows harder to make `PermissionProfile`-first.

External sandbox policies are intentionally excluded from this canonical
view. External enforcement cannot be round-tripped as a
`PermissionProfile`, and exposing a lossy root-write profile would let
clients accidentally change sandbox semantics if they echo the profile
back later.

## What changed

- Adds the app-server v2 `PermissionProfile` wire shape, including
filesystem permissions and glob scan depth metadata.
- Adds `PermissionProfileNetworkPermissions` so the profile response
does not expose active network state through the older
additional-permissions naming.
- Returns `permissionProfile` from thread start, resume, and fork
responses when the active sandbox can be represented as a
`PermissionProfile`.
- Keeps legacy `sandbox` in those responses for compatibility and
documents `permissionProfile` as canonical when present.
- Makes lifecycle `permissionProfile` nullable and returns `null` for
`ExternalSandbox` to avoid exposing a lossy profile.
- Regenerates the app-server JSON schema and TypeScript fixtures.

## Verification

- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-app-server
thread_response_permission_profile_omits_external_sandbox --
--nocapture`
- `cargo check --tests -p codex-analytics -p codex-exec -p codex-tui`
- `just fix -p codex-app-server-protocol -p codex-app-server -p
codex-analytics -p codex-exec -p codex-tui`

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/18278).
* #18279
* __->__ #18278

codex-rs/analytics/src/analytics_client_tests.rs

@@ -65,6 +65,7 @@ use codex_app_server_protocol::InitializeCapabilities;
 use codex_app_server_protocol::InitializeParams;
 use codex_app_server_protocol::JSONRPCErrorError;
 use codex_app_server_protocol::NonSteerableTurnKind;
+use codex_app_server_protocol::PermissionProfile as AppServerPermissionProfile;
 use codex_app_server_protocol::RequestId;
 use codex_app_server_protocol::SandboxPolicy as AppServerSandboxPolicy;
 use codex_app_server_protocol::ServerNotification;
@@ -91,6 +92,7 @@ use codex_plugin::PluginTelemetryMetadata;
 use codex_protocol::approvals::NetworkApprovalProtocol;
 use codex_protocol::config_types::ApprovalsReviewer;
 use codex_protocol::config_types::ModeKind;
+use codex_protocol::models::PermissionProfile as CorePermissionProfile;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::HookEventName;
 use codex_protocol::protocol::HookRunStatus;
@@ -152,11 +154,20 @@ fn sample_thread_start_response(thread_id: &str, ephemeral: bool, model: &str) -
             approval_policy: AppServerAskForApproval::OnFailure,
             approvals_reviewer: AppServerApprovalsReviewer::User,
             sandbox: AppServerSandboxPolicy::DangerFullAccess,
+            permission_profile: Some(sample_permission_profile()),
             reasoning_effort: None,
         },
     }
 }
 
+fn sample_permission_profile() -> AppServerPermissionProfile {
+    CorePermissionProfile::from_legacy_sandbox_policy(
+        &SandboxPolicy::DangerFullAccess,
+        &test_path_buf("/tmp"),
+    )
+    .into()
+}
+
 fn sample_app_server_client_metadata() -> CodexAppServerClientMetadata {
     CodexAppServerClientMetadata {
         product_client_id: DEFAULT_ORIGINATOR.to_string(),
@@ -203,6 +214,7 @@ fn sample_thread_resume_response_with_source(
             approval_policy: AppServerAskForApproval::OnFailure,
             approvals_reviewer: AppServerApprovalsReviewer::User,
             sandbox: AppServerSandboxPolicy::DangerFullAccess,
+            permission_profile: Some(sample_permission_profile()),
             reasoning_effort: None,
         },
     }