fix: address PR review comments

- Add error logging to CodexProvider auth check instead of silent failure
- Fix cachedAt timestamp to return actual cache time instead of request time
- Replace misleading hardcoded rate limit values (100) with sentinel value (-1)
- Fix unused parameter warning in codex routes

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/server/src/services/codex-usage-service.ts

@@ -157,9 +157,9 @@ export class CodexUsageService {
       if (rateLimitsResult?.rateLimits?.primary) {
         const primary = rateLimitsResult.rateLimits.primary;
         result.rateLimits!.primary = {
-          limit: 100, // Not provided by API, using placeholder
-          used: primary.usedPercent,
-          remaining: 100 - primary.usedPercent,
+          limit: -1, // Not provided by API
+          used: -1, // Not provided by API
+          remaining: -1, // Not provided by API
           usedPercent: primary.usedPercent,
           windowDurationMins: primary.windowDurationMins,
           resetsAt: primary.resetsAt,
@@ -170,9 +170,9 @@ export class CodexUsageService {
       if (rateLimitsResult?.rateLimits?.secondary) {
         const secondary = rateLimitsResult.rateLimits.secondary;
         result.rateLimits!.secondary = {
-          limit: 100,
-          used: secondary.usedPercent,
-          remaining: 100 - secondary.usedPercent,
+          limit: -1, // Not provided by API
+          used: -1, // Not provided by API
+          remaining: -1, // Not provided by API
           usedPercent: secondary.usedPercent,
           windowDurationMins: secondary.windowDurationMins,
           resetsAt: secondary.resetsAt,