protocol: report session permission profiles (#18282)

## Why

Clients that observe `SessionConfigured` need the same canonical
permission view that app-server thread responses provide. Reporting the
profile in protocol events lets clients keep their local state
synchronized without reinterpreting legacy sandbox fields.

## What changed

This adds `permission_profile` to `SessionConfigured` and propagates it
through core, exec JSON output, MCP server messages, and TUI
history/widget handling.

## Verification

- `cargo test -p codex-tui permissions -- --nocapture`
- `cargo test -p codex-core --test all permissions_messages --
--nocapture`















































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[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/18282).
* #18288
* #18287
* #18286
* #18285
* #18284
* #18283
* __->__ #18282

codex-rs/protocol/src/protocol.rs

@@ -3672,9 +3672,17 @@ pub struct SessionConfiguredEvent {
     #[serde(default)]
     pub approvals_reviewer: ApprovalsReviewer,
 
-    /// How to sandbox commands executed in the system
+    /// Legacy sandbox projection for commands executed in the system.
+    ///
+    /// Consumers should prefer `permission_profile` when it is present. This
+    /// field remains available as a compatibility fallback for older emitters
+    /// and sessions that only expose legacy sandbox state.
     pub sandbox_policy: SandboxPolicy,
 
+    /// Canonical effective permissions for commands executed in the session.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub permission_profile: Option<PermissionProfile>,
+
     /// Working directory that should be treated as the *root* of the
     /// session.
     pub cwd: AbsolutePathBuf,
@@ -5249,6 +5257,7 @@ mod tests {
                 approval_policy: AskForApproval::Never,
                 approvals_reviewer: ApprovalsReviewer::User,
                 sandbox_policy: SandboxPolicy::new_read_only_policy(),
+                permission_profile: None,
                 cwd: test_path_buf("/home/user/project").abs(),
                 reasoning_effort: Some(ReasoningEffortConfig::default()),
                 history_log_id: 0,