permissions: derive compatibility policies from profiles (#19392)

## Why

After #19391, `PermissionProfile` and the split filesystem/network
policies could still be stored in parallel. That creates drift risk: a
profile can preserve deny globs, external enforcement, or split
filesystem entries while a cached projection silently loses those
details. This PR makes the profile the runtime source and derives
compatibility views from it.

## What Changed

- Removes stored filesystem/network sandbox projections from
`Permissions` and `SessionConfiguration`; their accessors now derive
from the canonical `PermissionProfile`.
- Derives legacy `SandboxPolicy` snapshots from profiles only where an
older API still needs that field.
- Updates MCP connection and elicitation state to track
`PermissionProfile` instead of `SandboxPolicy` for auto-approval
decisions.
- Adds semantic filesystem-policy comparison so cwd changes can preserve
richer profiles while still recognizing equivalent legacy projections
independent of entry ordering.
- Updates config/session tests to assert profile-derived projections
instead of parallel stored fields.

## Verification

- `cargo test -p codex-core direct_write_roots`
- `cargo test -p codex-core runtime_roots_to_legacy_projection`
- `cargo test -p codex-app-server
requested_permissions_trust_project_uses_permission_profile_intent`



































































---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/19392).
* #19395
* #19394
* #19393
* __->__ #19392

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

@@ -14,10 +14,12 @@ use codex_config::types::McpServerConfig;
 use codex_config::types::McpServerTransportConfig;
 use codex_core::sandboxing::SandboxPermissions;
 use codex_features::Feature;
+use codex_protocol::models::PermissionProfile;
 use codex_protocol::permissions::FileSystemAccessMode;
 use codex_protocol::permissions::FileSystemPath;
 use codex_protocol::permissions::FileSystemSandboxEntry;
 use codex_protocol::permissions::FileSystemSandboxPolicy;
+use codex_protocol::permissions::NetworkSandboxPolicy;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::SandboxPolicy;
 use codex_protocol::protocol::TurnEnvironmentSelection;
@@ -560,7 +562,11 @@ async fn shell_enforces_glob_deny_read_policy() -> Result<()> {
                     },
                     access: FileSystemAccessMode::None,
                 });
-            config.permissions.file_system_sandbox_policy = file_system_sandbox_policy;
+            config.permissions.permission_profile =
+                Constrained::allow_any(PermissionProfile::from_runtime_permissions(
+                    &file_system_sandbox_policy,
+                    NetworkSandboxPolicy::Restricted,
+                ));
         });
     let fixture = builder.build(&server).await?;