fix(voice): validate Codex OAuth and report unknown usage

src/voice/realtimeCost.js

@@ -19,6 +19,7 @@ export class RealtimeCost {
     this.voiceLimits = readStoredVoiceLimits();
     this.cloudVoiceAuth = readStoredCloudVoiceAuthMode();
     this.sessionCloudVoiceAuth = null;
+    this.oauthUsage = { responses: 0, input: 0, output: 0 };
     this.costTracker = createVoiceCostTracker({
       tier: this.voiceTier,
       limits: this.voiceLimits,
@@ -60,7 +61,20 @@ export class RealtimeCost {
     }
     if (this.ui?.costValue) {
       const liveAuth = this.sessionCloudVoiceAuth || this.cloudVoiceAuth;
-      this.ui.costValue.hidden = liveAuth === 'oauth';
+      if (liveAuth === 'oauth') {
+        const { responses, input, output } = this.oauthUsage;
+        this.ui.costValue.hidden = false;
+        this.ui.costValue.textContent = 'COST UNKNOWN';
+        this.ui.costValue.dataset.level = 'unknown';
+        this.ui.costValue.title =
+          `ChatGPT OAuth session: ${responses} response(s), ${input} input and ${output} output tokens reported. ` +
+          'USD cost and the API spend cap are unavailable for this auth mode.' +
+          (state.incomplete
+            ? ' Usage is incomplete because a response was still in flight when the session ended.'
+            : '');
+        return;
+      }
+      this.ui.costValue.hidden = false;
       this.ui.costValue.textContent = state.display;
       this.ui.costValue.dataset.level = state.level;
       this.ui.costValue.title =
@@ -141,7 +155,15 @@ export class RealtimeCost {
    */
   recordUsage(usage) {
     if (!usage) return null;
-    if (this.sessionCloudVoiceAuth === 'oauth') return null;
+    if (this.sessionCloudVoiceAuth === 'oauth') {
+      const count = (value) =>
+        Number.isFinite(value) && value > 0 ? value : 0;
+      this.oauthUsage.responses += 1;
+      this.oauthUsage.input += count(usage.input_tokens);
+      this.oauthUsage.output += count(usage.output_tokens);
+      this.syncCostUi();
+      return { ...this.oauthUsage, costKnown: false };
+    }
     const state = this.costTracker.record(usage);
     this.syncCostUi();
     if (state.warnCrossed) {
@@ -198,6 +220,7 @@ export class RealtimeCost {
     this.voiceLimits = readStoredVoiceLimits();
     this.cloudVoiceAuth = readStoredCloudVoiceAuthMode();
     this.sessionCloudVoiceAuth = this.cloudVoiceAuth;
+    this.oauthUsage = { responses: 0, input: 0, output: 0 };
     this.costCapStopped = false;
     // Provisional meter (tier-priced) so the readout shows $0.00 while
     // connecting. It is REPLACED below with one bound to the model the server