fix(cli): format stats with Locale.ROOT so output is locale-independent

renderStats used the default-locale String.format, so under a comma-decimal
locale (e.g. ru_RU) percentages/rates rendered as "58,3" — both producing
locale-dependent CLI output and failing StatsRenderTest. Format all five
numeric rows with Locale.ROOT.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/cli/src/main/kotlin/com/correx/apps/cli/commands/StatsCommand.kt

@@ -13,6 +13,7 @@ import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
 import io.ktor.client.request.get
 import io.ktor.client.statement.bodyAsText
 import io.ktor.serialization.kotlinx.json.json
+import java.util.Locale
 import kotlinx.coroutines.runBlocking
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.Json
@@ -110,9 +111,10 @@ fun renderStats(report: StatsReportDto): String {
     lines += "  calls:      ${report.inferenceCount}"
     lines += "  tokens:     ${report.promptTokens} prompt + ${report.completionTokens} completion = " +
         "${report.promptTokens + report.completionTokens}"
-    lines += "  time:       ${report.inferenceMs} ms  (%.1f tok/s)".format(report.tokensPerSecond)
+    lines += "  time:       ${report.inferenceMs} ms  (%.1f tok/s)".format(Locale.ROOT, report.tokensPerSecond)
     for (p in report.perProvider) {
         lines += "    %-20s %4d calls  %6d tok  %8d ms  (%.1f tok/s)".format(
+            Locale.ROOT,
             p.provider, p.completedCount, p.promptTokens + p.completionTokens, p.totalLatencyMs, p.tokensPerSecond,
         )
     }
@@ -121,7 +123,7 @@ fun renderStats(report: StatsReportDto): String {
     lines += "Tools"
     lines += "  calls:      ${report.toolCount}   time: ${report.toolMs} ms"
     for (t in report.perTool) {
-        lines += "    %-24s %4d  %8d ms".format(t.toolName, t.completedCount, t.totalDurationMs)
+        lines += "    %-24s %4d  %8d ms".format(Locale.ROOT, t.toolName, t.completedCount, t.totalDurationMs)
     }
     lines += ""
 
@@ -131,6 +133,7 @@ fun renderStats(report: StatsReportDto): String {
     lines += "  total wait: ${report.approvalWaitMs} ms  (avg ${report.avgApprovalWaitMs} ms)"
     for (tier in report.perTier) {
         lines += "    %-4s req %d  res %d  wait %d ms (avg %d ms)".format(
+            Locale.ROOT,
             tier.tier, tier.requestedCount, tier.resolvedCount, tier.totalWaitMs, tier.avgWaitMs,
         )
     }
@@ -145,6 +148,7 @@ fun renderStats(report: StatsReportDto): String {
 
     lines += "Time accounting (% of session wall time)"
     lines += "  inference: %.1f%%   tools: %.1f%%   approval-wait: %.1f%%   other: %.1f%%".format(
+        Locale.ROOT,
         report.inferencePct, report.toolPct, report.approvalWaitPct, otherPct(report),
     )