Add per-app tool exposure configuration (#46035)

## Why

Server-level tool exposure settings apply to every connector on the apps server. Individual connectors need a way to opt out of deferred discovery without changing exposure for other apps.

## What changed

Add `apps.<connector_id>.omit_tools_from` with support for `code_mode`, `deferred`, and `direct`. Combine connector omissions with server omissions so app settings preserve server restrictions.

For example, `omit_tools_from = ["deferred"]` makes a connector's tools available without tool search, through direct calls or Code Mode as permitted by the active tool mode and remaining restrictions.

Expose the setting in the app-server protocol, JSON schemas, and generated TypeScript and Python types.

## Testing

Add integration coverage for connector-specific exposure and MCP dispatch across tool modes, server restrictions, and direct-only namespaces. Extend config tests to cover populated, absent, and empty omission lists, and add a Code Mode request-history snapshot.

GitOrigin-RevId: cc99ab290c8a878d06d8d7ccf2d1dbd7c46bfa8a

codex-rs/app-server-protocol/src/protocol/v2/config.rs

@@ -12,6 +12,7 @@ use codex_experimental_api_macros::ExperimentalApi;
 use codex_protocol::config_types::AutoCompactTokenLimitScope;
 use codex_protocol::config_types::ForcedLoginMethod;
 use codex_protocol::config_types::ReasoningSummary;
+use codex_protocol::config_types::ToolExposureSurface;
 use codex_protocol::config_types::Verbosity;
 use codex_protocol::config_types::WebSearchMode;
 use codex_protocol::config_types::WebSearchToolConfig;
@@ -234,6 +235,8 @@ pub struct AppLinksConfig {
 pub struct AppConfig {
     #[serde(default = "default_enabled")]
     pub enabled: bool,
+    /// Additional model-facing surfaces omitted for this connector's tools.
+    pub omit_tools_from: Option<Vec<ToolExposureSurface>>,
     pub approvals_reviewer: Option<ApprovalsReviewer>,
     pub destructive_enabled: Option<bool>,
     pub open_world_enabled: Option<bool>,