feat: introduce Permissions (#11633)

## Why
We currently carry multiple permission-related concepts directly on
`Config` for shell/unified-exec behavior (`approval_policy`,
`sandbox_policy`, `network`, `shell_environment_policy`,
`windows_sandbox_mode`).

Consolidating these into one in-memory struct makes permission handling
easier to reason about and sets up the next step: supporting named
permission profiles (`[permissions.PROFILE_NAME]`) without changing
behavior now.

This change is mostly mechanical: it updates existing callsites to go
through `config.permissions`, but it does not yet refactor those
callsites to take a single `Permissions` value in places where multiple
permission fields are still threaded separately.

This PR intentionally **does not** change the on-disk `config.toml`
format yet and keeps compatibility with legacy config keys.

## What Changed
- Introduced `Permissions` in `core/src/config/mod.rs`.
- Added `Config::permissions` and moved effective runtime permission
fields under it:
  - `approval_policy`
  - `sandbox_policy`
  - `network`
  - `shell_environment_policy`
  - `windows_sandbox_mode`
- Updated config loading/building so these effective values are still
derived from the same existing config inputs and constraints.
- Updated Windows sandbox helpers/resolution to read/write via
`permissions`.
- Threaded the new field through all permission consumers across core
runtime, app-server, CLI/exec, TUI, and sandbox summary code.
- Updated affected tests to reference `config.permissions.*`.
- Renamed the struct/field from
`EffectivePermissions`/`effective_permissions` to
`Permissions`/`permissions` and aligned variable naming accordingly.

## Verification
- `just fix -p codex-core -p codex-tui -p codex-cli -p codex-app-server
-p codex-exec -p codex-utils-sandbox-summary`
- `cargo build -p codex-core -p codex-tui -p codex-cli -p
codex-app-server -p codex-exec -p codex-utils-sandbox-summary`

codex-rs/core/tests/suite/personality.rs

@@ -94,7 +94,7 @@ async fn user_turn_personality_none_does_not_add_update_message() -> anyhow::Res
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -141,7 +141,7 @@ async fn config_personality_some_sets_instructions_template() -> anyhow::Result<
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -195,7 +195,7 @@ async fn config_personality_none_sends_no_personality() -> anyhow::Result<()> {
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -255,7 +255,7 @@ async fn default_personality_is_pragmatic_without_config_toml() -> anyhow::Resul
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -303,7 +303,7 @@ async fn user_turn_personality_some_adds_update_message() -> anyhow::Result<()>
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -337,7 +337,7 @@ async fn user_turn_personality_some_adds_update_message() -> anyhow::Result<()>
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -400,7 +400,7 @@ async fn user_turn_personality_same_value_does_not_add_update_message() -> anyho
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -434,7 +434,7 @@ async fn user_turn_personality_same_value_does_not_add_update_message() -> anyho
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -507,7 +507,7 @@ async fn user_turn_personality_skips_if_feature_disabled() -> anyhow::Result<()>
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,
@@ -541,7 +541,7 @@ async fn user_turn_personality_skips_if_feature_disabled() -> anyhow::Result<()>
             }],
             final_output_json_schema: None,
             cwd: test.cwd_path().to_path_buf(),
-            approval_policy: test.config.approval_policy.value(),
+            approval_policy: test.config.permissions.approval_policy.value(),
             sandbox_policy: SandboxPolicy::new_read_only_policy(),
             model: test.session_configured.model.clone(),
             effort: test.config.model_reasoning_effort,