Propagate permission approval environment id (#25862)

## Stack

1. #25850 - Key request-permission grants by environment: stores and
applies sticky permission grants per environment id.
2. #25858 - Add `environmentId` to `request_permissions`: lets the model
target a selected environment and resolves relative permission paths
against it.
3. This PR (#25862) - Propagate permission approval environment id:
carries the selected environment id through approval events, app-server
requests, TUI prompts, and delegate forwarding.
4. #25867 - Add remote request permissions integration coverage:
verifies the selected remote environment across request, approval, grant
reuse, and exec.

This PR is stacked on #25858, and #25867 is stacked on this PR.

## Why

PR2 lets the model bind a `request_permissions` call to a selected
environment, but the approval event and client-facing request still
needed to carry that binding. For CCA, the user-facing prompt and
delegated approval path should know which environment the grant applies
to instead of relying on cwd alone.

## What Changed

- Added optional `environmentId` to `RequestPermissionsEvent`.
- Emit the selected environment id from core permission approval events.
- Preserve the environment id through delegate forwarding, including
cwd-based delegated requests.
- Added `environmentId` to app-server permission approval params,
generated schema/TypeScript artifacts, and README examples.
- Preserve and display the environment id in TUI permission approval
prompts.
- Updated focused core, app-server protocol, and TUI conversion
coverage.

## Testing

Not run locally per instruction. Performed read-only `git diff --check`.

codex-rs/protocol/src/request_permissions.rs

@@ -79,6 +79,15 @@ pub struct RequestPermissionsEvent {
     /// Uses `#[serde(default)]` for backwards compatibility.
     #[serde(default)]
     pub turn_id: String,
+    #[serde(
+        default,
+        rename = "environmentId",
+        alias = "environment_id",
+        skip_serializing_if = "Option::is_none"
+    )]
+    #[ts(optional)]
+    #[ts(rename = "environmentId")]
+    pub environment_id: Option<String>,
     #[ts(type = "number")]
     pub started_at_ms: i64,
     #[serde(skip_serializing_if = "Option::is_none")]