fix: implement 'Allow this session' for apply_patch approvals (#8451)

**Summary**
This PR makes “ApprovalDecision::AcceptForSession / don’t ask again this
session” actually work for `apply_patch` approvals by caching approvals
based on absolute file paths in codex-core, properly wiring it through
app-server v2, and exposing the choice in both TUI and TUI2.
- This brings `apply_patch` calls to be at feature-parity with general
shell commands, which also have a "Yes, and don't ask again" option.
- This also fixes VSCE's "Allow this session" button to actually work.

While we're at it, also split the app-server v2 protocol's
`ApprovalDecision` enum so execpolicy amendments are only available for
command execution approvals.

**Key changes**
- Core: per-session patch approval allowlist keyed by absolute file
paths
- Handles multi-file patches and renames/moves by recording both source
and destination paths for `Update { move_path: Some(...) }`.
- Extend the `Approvable` trait and `ApplyPatchRuntime` to work with
multiple keys, because an `apply_patch` tool call can modify multiple
files. For a request to be auto-approved, we will need to check that all
file paths have been approved previously.
- App-server v2: honor AcceptForSession for file changes
- File-change approval responses now map AcceptForSession to
ReviewDecision::ApprovedForSession (no longer downgraded to plain
Approved).
- Replace `ApprovalDecision` with two enums:
`CommandExecutionApprovalDecision` and `FileChangeApprovalDecision`
- TUI / TUI2: expose “don’t ask again for these files this session”
- Patch approval overlays now include a third option (“Yes, and don’t
ask again for these files this session (s)”).
    - Snapshot updates for the approval modal.

**Tests added/updated**
- Core:
- Integration test that proves ApprovedForSession on a patch skips the
next patch prompt for the same file
- App-server:
- v2 integration test verifying
FileChangeApprovalDecision::AcceptForSession works properly

**User-visible behavior**
- When the user approves a patch “for session”, future patches touching
only those previously approved file(s) will no longer prompt gain during
that session (both via app-server v2 and TUI/TUI2).

**Manual testing**
Tested both TUI and TUI2 - see screenshots below.

TUI:
<img width="1082" height="355" alt="image"
src="https://github.com/user-attachments/assets/adcf45ad-d428-498d-92fc-1a0a420878d9"
/>


TUI2:
<img width="1089" height="438" alt="image"
src="https://github.com/user-attachments/assets/dd768b1a-2f5f-4bd6-98fd-e52c1d3abd9e"
/>

codex-rs/app-server/src/bespoke_event_handling.rs

@@ -13,9 +13,9 @@ use codex_app_server_protocol::AccountRateLimitsUpdatedNotification;
 use codex_app_server_protocol::AgentMessageDeltaNotification;
 use codex_app_server_protocol::ApplyPatchApprovalParams;
 use codex_app_server_protocol::ApplyPatchApprovalResponse;
-use codex_app_server_protocol::ApprovalDecision;
 use codex_app_server_protocol::CodexErrorInfo as V2CodexErrorInfo;
 use codex_app_server_protocol::CommandAction as V2ParsedCommand;
+use codex_app_server_protocol::CommandExecutionApprovalDecision;
 use codex_app_server_protocol::CommandExecutionOutputDeltaNotification;
 use codex_app_server_protocol::CommandExecutionRequestApprovalParams;
 use codex_app_server_protocol::CommandExecutionRequestApprovalResponse;
@@ -26,6 +26,7 @@ use codex_app_server_protocol::ErrorNotification;
 use codex_app_server_protocol::ExecCommandApprovalParams;
 use codex_app_server_protocol::ExecCommandApprovalResponse;
 use codex_app_server_protocol::ExecPolicyAmendment as V2ExecPolicyAmendment;
+use codex_app_server_protocol::FileChangeApprovalDecision;
 use codex_app_server_protocol::FileChangeOutputDeltaNotification;
 use codex_app_server_protocol::FileChangeRequestApprovalParams;
 use codex_app_server_protocol::FileChangeRequestApprovalResponse;
@@ -1193,6 +1194,21 @@ fn format_file_change_diff(change: &CoreFileChange) -> String {
     }
 }
 
+fn map_file_change_approval_decision(
+    decision: FileChangeApprovalDecision,
+) -> (ReviewDecision, Option<PatchApplyStatus>) {
+    match decision {
+        FileChangeApprovalDecision::Accept => (ReviewDecision::Approved, None),
+        FileChangeApprovalDecision::AcceptForSession => (ReviewDecision::ApprovedForSession, None),
+        FileChangeApprovalDecision::Decline => {
+            (ReviewDecision::Denied, Some(PatchApplyStatus::Declined))
+        }
+        FileChangeApprovalDecision::Cancel => {
+            (ReviewDecision::Abort, Some(PatchApplyStatus::Declined))
+        }
+    }
+}
+
 #[allow(clippy::too_many_arguments)]
 async fn on_file_change_request_approval_response(
     event_turn_id: String,
@@ -1211,23 +1227,12 @@ async fn on_file_change_request_approval_response(
                 .unwrap_or_else(|err| {
                     error!("failed to deserialize FileChangeRequestApprovalResponse: {err}");
                     FileChangeRequestApprovalResponse {
-                        decision: ApprovalDecision::Decline,
+                        decision: FileChangeApprovalDecision::Decline,
                     }
                 });
 
-            let (decision, completion_status) = match response.decision {
-                ApprovalDecision::Accept
-                | ApprovalDecision::AcceptForSession
-                | ApprovalDecision::AcceptWithExecpolicyAmendment { .. } => {
-                    (ReviewDecision::Approved, None)
-                }
-                ApprovalDecision::Decline => {
-                    (ReviewDecision::Denied, Some(PatchApplyStatus::Declined))
-                }
-                ApprovalDecision::Cancel => {
-                    (ReviewDecision::Abort, Some(PatchApplyStatus::Declined))
-                }
-            };
+            let (decision, completion_status) =
+                map_file_change_approval_decision(response.decision);
             // Allow EventMsg::PatchApplyEnd to emit ItemCompleted for accepted patches.
             // Only short-circuit on declines/cancels/failures.
             (decision, completion_status)
@@ -1281,16 +1286,18 @@ async fn on_command_execution_request_approval_response(
                 .unwrap_or_else(|err| {
                     error!("failed to deserialize CommandExecutionRequestApprovalResponse: {err}");
                     CommandExecutionRequestApprovalResponse {
-                        decision: ApprovalDecision::Decline,
+                        decision: CommandExecutionApprovalDecision::Decline,
                     }
                 });
 
             let decision = response.decision;
 
             let (decision, completion_status) = match decision {
-                ApprovalDecision::Accept => (ReviewDecision::Approved, None),
-                ApprovalDecision::AcceptForSession => (ReviewDecision::ApprovedForSession, None),
-                ApprovalDecision::AcceptWithExecpolicyAmendment {
+                CommandExecutionApprovalDecision::Accept => (ReviewDecision::Approved, None),
+                CommandExecutionApprovalDecision::AcceptForSession => {
+                    (ReviewDecision::ApprovedForSession, None)
+                }
+                CommandExecutionApprovalDecision::AcceptWithExecpolicyAmendment {
                     execpolicy_amendment,
                 } => (
                     ReviewDecision::ApprovedExecpolicyAmendment {
@@ -1298,11 +1305,11 @@ async fn on_command_execution_request_approval_response(
                     },
                     None,
                 ),
-                ApprovalDecision::Decline => (
+                CommandExecutionApprovalDecision::Decline => (
                     ReviewDecision::Denied,
                     Some(CommandExecutionStatus::Declined),
                 ),
-                ApprovalDecision::Cancel => (
+                CommandExecutionApprovalDecision::Cancel => (
                     ReviewDecision::Abort,
                     Some(CommandExecutionStatus::Declined),
                 ),
@@ -1442,6 +1449,14 @@ mod tests {
         Arc::new(Mutex::new(HashMap::new()))
     }
 
+    #[test]
+    fn file_change_accept_for_session_maps_to_approved_for_session() {
+        let (decision, completion_status) =
+            map_file_change_approval_decision(FileChangeApprovalDecision::AcceptForSession);
+        assert_eq!(decision, ReviewDecision::ApprovedForSession);
+        assert_eq!(completion_status, None);
+    }
+
     #[tokio::test]
     async fn test_handle_error_records_message() -> Result<()> {
         let conversation_id = ThreadId::new();