unified-exec: retain PathUri in command events (#28780)

## Why

App-server must report command events containing foreign-platform paths
without changing existing client or rollout path-string formats.

## What changed

- retain `PathUri` through exec command begin/end events
- convert cwd values to `LegacyAppPathString` at the app-server
compatibility boundary
- drop command actions with foreign paths and log them
- serialize rollout-trace cwd values using their inferred native path
representation
- restore Wine coverage for retained Windows cwd values and successful
completion

codex-rs/app-server-protocol/src/protocol/item_builders_tests.rs

@@ -0,0 +1,41 @@
+use super::*;
+use pretty_assertions::assert_eq;
+
+#[test]
+fn foreign_read_is_omitted_without_dropping_other_command_actions() {
+    #[cfg(windows)]
+    let cwd = PathUri::parse("file:///usr/local/src").expect("valid foreign POSIX cwd");
+    #[cfg(not(windows))]
+    let cwd = PathUri::parse("file:///C:/src").expect("valid foreign Windows cwd");
+    let parsed_cmd = vec![
+        ParsedCommand::Read {
+            cmd: "cat file.txt".to_string(),
+            name: "file.txt".to_string(),
+            path: PathBuf::from("file.txt"),
+        },
+        ParsedCommand::ListFiles {
+            cmd: "ls".to_string(),
+            path: Some("subdir".to_string()),
+        },
+        ParsedCommand::Search {
+            cmd: "rg needle".to_string(),
+            query: Some("needle".to_string()),
+            path: Some("src".to_string()),
+        },
+    ];
+
+    assert_eq!(
+        command_actions_for_path_uri(&parsed_cmd, &cwd),
+        vec![
+            CommandAction::ListFiles {
+                command: "ls".to_string(),
+                path: Some("subdir".to_string()),
+            },
+            CommandAction::Search {
+                command: "rg needle".to_string(),
+                query: Some("needle".to_string()),
+                path: Some("src".to_string()),
+            },
+        ]
+    );
+}