fix: tighten up some logic around session timestamps and ids (#922)

* update `SessionConfigured` event to include the UUID for the session
* show the UUID in the Rust TUI
* use local timestamps in log files instead of UTC
* include timestamps in log file names for easier discovery

codex-rs/tui/Cargo.toml

@@ -42,3 +42,4 @@ tracing-subscriber = { version = "0.3.19", features = ["env-filter"] }
 tui-input = "0.11.1"
 tui-markdown = "0.3.3"
 tui-textarea = "0.7.0"
+uuid = { version = "1" }