permissions: remove macOS seatbelt extension profiles (#15918)

## Why

`PermissionProfile` should only describe the per-command permissions we
still want to grant dynamically. Keeping
`MacOsSeatbeltProfileExtensions` in that surface forced extra macOS-only
approval, protocol, schema, and TUI branches for a capability we no
longer want to expose.

## What changed

- Removed the macOS-specific permission-profile types from
`codex-protocol`, the app-server v2 API, and the generated
schema/TypeScript artifacts.
- Deleted the core and sandboxing plumbing that threaded
`MacOsSeatbeltProfileExtensions` through execution requests and seatbelt
construction.
- Simplified macOS seatbelt generation so it always includes the fixed
read-only preferences allowlist instead of carrying a configurable
profile extension.
- Removed the macOS additional-permissions UI/docs/test coverage and
deleted the obsolete macOS permission modules.
- Tightened `request_permissions` intersection handling so explicitly
empty requested read lists are preserved only when that field was
actually granted, avoiding zero-grant responses being stored as active
permissions.

codex-rs/core/src/config/mod.rs

@@ -78,7 +78,6 @@ use codex_protocol::config_types::WebSearchConfig;
 use codex_protocol::config_types::WebSearchMode;
 use codex_protocol::config_types::WebSearchToolConfig;
 use codex_protocol::config_types::WindowsSandboxLevel;
-use codex_protocol::models::MacOsSeatbeltProfileExtensions;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::openai_models::ReasoningEffort;
 use codex_protocol::permissions::FileSystemSandboxPolicy;
@@ -206,9 +205,6 @@ pub struct Permissions {
     pub windows_sandbox_mode: Option<WindowsSandboxModeToml>,
     /// Whether the final Windows sandboxed child should run on a private desktop.
     pub windows_sandbox_private_desktop: bool,
-    /// Optional macOS seatbelt extension profile used to extend default
-    /// seatbelt permissions when running under seatbelt.
-    pub macos_seatbelt_profile_extensions: Option<MacOsSeatbeltProfileExtensions>,
 }
 
 /// Application configuration loaded from disk and merged with overrides.
@@ -2556,7 +2552,6 @@ impl Config {
                 shell_environment_policy,
                 windows_sandbox_mode,
                 windows_sandbox_private_desktop,
-                macos_seatbelt_profile_extensions: None,
             },
             approvals_reviewer,
             enforce_residency: enforce_residency.value,