chore: enable clippy::redundant_clone (#3489)

Created this PR by:

- adding `redundant_clone` to `[workspace.lints.clippy]` in
`cargo-rs/Cargol.toml`
- running `cargo clippy --tests --fix`
- running `just fmt`

Though I had to clean up one instance of the following that resulted:

```rust
let codex = codex;
```

codex-rs/exec/src/event_processor_with_human_output.rs

@@ -280,7 +280,7 @@ impl EventProcessor for EventProcessorWithHumanOutput {
                 parsed_cmd: _,
             }) => {
                 self.call_id_to_command.insert(
-                    call_id.clone(),
+                    call_id,
                     ExecCommandBegin {
                         command: command.clone(),
                     },
@@ -382,7 +382,7 @@ impl EventProcessor for EventProcessorWithHumanOutput {
                 // Store metadata so we can calculate duration later when we
                 // receive the corresponding PatchApplyEnd event.
                 self.call_id_to_patch.insert(
-                    call_id.clone(),
+                    call_id,
                     PatchApplyBegin {
                         start_time: Instant::now(),
                         auto_approved,

codex-rs/exec/tests/suite/common.rs

@@ -61,7 +61,7 @@ pub(crate) async fn run_e2e_exec_test(cwd: &Path, response_streams: Vec<String>)
         .context("should find binary for codex-exec")
         .expect("should find binary for codex-exec")
         .current_dir(cwd.clone())
-        .env("CODEX_HOME", cwd.clone())
+        .env("CODEX_HOME", cwd)
         .env("OPENAI_API_KEY", "dummy")
         .env("OPENAI_BASE_URL", format!("{uri}/v1"))
         .arg("--skip-git-repo-check")