build(native): bump pyo3 to 0.26 for Python 3.13 support

Author: gersmann

crates/codex_native/Cargo.toml

@@ -8,7 +8,7 @@ name = "codex_native"
 crate-type = ["cdylib"]
 
 [dependencies]
-pyo3 = { version = "0.21", features = ["extension-module"] }
+pyo3 = { version = "0.26", features = ["extension-module"] }
 anyhow = "1"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"