fix(primer): refresh Codex usage before primer and allow 1% fresh accounts

Codex primer was skipping with no_eligible_accounts because it read a
stale usage cache and required exactly 0% usage. Re-query usage right
before the primer call and treat freshly-reset 0~1% accounts as eligible
so the 5h window can be anchored at the fixed KST slot. Also hold new
Codex-owner turns at fresh usage until the next primer slot.

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>

src/message-runtime-gating.ts

@@ -6,6 +6,7 @@ import {
   CODEX_EXHAUSTION_THRESHOLD_PCT,
   getCodexUsageExhaustion,
 } from './codex-usage-collector.js';
+import { getAllCodexAccounts } from './codex-token-rotation.js';
 import { logger } from './logger.js';
 import {
   handleSessionCommand,
@@ -66,16 +67,65 @@ function exhaustionMessageFor(
 // is processed anyway — user explicitly tagged the bot, accept the drift.
 const GAP_START_HOUR_KST = 4;
 const GAP_END_HOUR_KST = 8;
+const PRIMER_HOURS_KST = [8, 13, 18, 23];
 const KST_OFFSET_MS = 9 * 60 * 60 * 1000;
+const CODEX_ALIGNMENT_FRESH_USAGE_PCT = 1;
+const PRIMER_GRACE_MS = 2 * 60 * 1000;
 
 export function isInUsageAlignmentGap(nowMs: number = Date.now()): boolean {
   const kstHour = new Date(nowMs + KST_OFFSET_MS).getUTCHours();
   return kstHour >= GAP_START_HOUR_KST && kstHour < GAP_END_HOUR_KST;
 }
 
+function msUntilNextPrimerSlotKST(nowMs: number): number {
+  const kstNowShifted = nowMs + KST_OFFSET_MS;
+  const kstDate = new Date(kstNowShifted);
+  const kstH = kstDate.getUTCHours();
+
+  let nextH = PRIMER_HOURS_KST.find((h) => h > kstH);
+  let dayOffset = 0;
+  if (nextH === undefined) {
+    nextH = PRIMER_HOURS_KST[0];
+    dayOffset = 1;
+  }
+
+  const target = new Date(kstNowShifted);
+  target.setUTCHours(nextH, 0, 0, 0);
+  if (dayOffset === 1) target.setUTCDate(target.getUTCDate() + 1);
+  return target.getTime() - kstNowShifted;
+}
+
+function formatPrimerHourKST(nowMs: number): string {
+  const nextMs = nowMs + msUntilNextPrimerSlotKST(nowMs);
+  const kst = new Date(nextMs + KST_OFFSET_MS);
+  return `${String(kst.getUTCHours()).padStart(2, '0')}:00 KST`;
+}
+
+export function shouldHoldFreshCodexUntilPrimer(
+  nowMs: number = Date.now(),
+): boolean {
+  const accounts = getAllCodexAccounts();
+  const active = accounts.find((a) => a.isActive) ?? accounts[0];
+  if (!active || active.isRateLimited) return false;
+  const h5 = active.cachedUsagePct;
+  if (h5 == null || h5 < 0 || h5 > CODEX_ALIGNMENT_FRESH_USAGE_PCT) {
+    return false;
+  }
+
+  const elapsedFromPreviousSlot =
+    (5 * 60 * 60 * 1000 - msUntilNextPrimerSlotKST(nowMs)) %
+    (5 * 60 * 60 * 1000);
+  return elapsedFromPreviousSlot > PRIMER_GRACE_MS;
+}
+
 const GAP_AUTO_REPLY =
   '사용량 정렬 시간(04~08 KST)입니다. 08시 이후 다시 보내주세요. 긴급한 경우 @태그하면 처리됩니다.';
 
+const CODEX_ALIGNMENT_AUTO_REPLY = (nowMs: number) =>
+  `Codex 사용량 정렬 대기 중입니다. 다음 프라이머 시각(${formatPrimerHourKST(
+    nowMs,
+  )}) 이후 다시 보내주세요. 긴급한 경우 @태그하면 처리됩니다.`;
+
 export async function handleQueuedRunGates(args: {
   chatJid: string;
   group: RegisteredGroup;
@@ -125,11 +175,35 @@ export async function handleQueuedRunGates(args: {
     }
   }
 
+  const agentType: AgentType = args.group.agentType ?? 'claude-code';
+  if (agentType === 'codex' && shouldHoldFreshCodexUntilPrimer()) {
+    const hasUrgentMention = args.missedMessages.some((m) =>
+      args.triggerPattern.test(m.content),
+    );
+    if (!hasUrgentMention) {
+      logger.info(
+        {
+          chatJid: args.chatJid,
+          groupName: args.group.name,
+          runId: args.runId,
+        },
+        'Blocking new Codex turn — waiting for fixed primer slot',
+      );
+      try {
+        await args.sessionCommandDeps.sendMessage(
+          CODEX_ALIGNMENT_AUTO_REPLY(Date.now()),
+        );
+      } catch (err) {
+        logger.warn({ err }, 'Failed to send Codex alignment notice');
+      }
+      return { handled: true, success: true };
+    }
+  }
+
   // ── Usage-exhaustion gate ──
   // Block new turns when the agent provider that would handle this room has
   // every account at ≥95% on either window (or rate-limited). In-flight
   // runs are not affected; this only stops *new* turns from starting.
-  const agentType: AgentType = args.group.agentType ?? 'claude-code';
   const info =
     agentType === 'codex'
       ? exhaustionChecks.codex()