[fix] fix absolute and % token counts (#1931)

- For absolute, use non-cached input + output.
- For estimating what % of the model's context window is used, we need
to account for reasoning output tokens from prior turns being dropped
from the context window. We approximate this here by subtracting
reasoning output tokens from the total. This will be off for the current
turn and pending function calls. We can improve it later.

codex-rs/exec/src/event_processor_with_human_output.rs

@@ -21,7 +21,6 @@ use codex_core::protocol::PatchApplyBeginEvent;
 use codex_core::protocol::PatchApplyEndEvent;
 use codex_core::protocol::SessionConfiguredEvent;
 use codex_core::protocol::TaskCompleteEvent;
-use codex_core::protocol::TokenUsage;
 use codex_core::protocol::TurnDiffEvent;
 use owo_colors::OwoColorize;
 use owo_colors::Style;
@@ -183,8 +182,8 @@ impl EventProcessor for EventProcessorWithHumanOutput {
                 }
                 return CodexStatus::InitiateShutdown;
             }
-            EventMsg::TokenCount(TokenUsage { total_tokens, .. }) => {
-                ts_println!(self, "tokens used: {total_tokens}");
+            EventMsg::TokenCount(token_usage) => {
+                ts_println!(self, "tokens used: {}", token_usage.blended_total());
             }
             EventMsg::AgentMessageDelta(AgentMessageDeltaEvent { delta }) => {
                 if !self.answer_started {