state: XAUTOCLAIM 空闲阈值改由运行超时配置推导，封顶 6h（01a0e75f-f9b1）

现状：read_batch 里 const SINGLE_EVENT_CEILING_MS = 300_000 是硬编码，
而真实单事件上限 = (max_retries+1) x (jmap+telegram+llm 三个 timeout)，
运维把任一超时调大后实际耗时可能远超 300s → 空闲阈值欠保护，
多实例会把还在处理的条目提前认领，造成重复投递。

改动（ROADMAP 缺口③「多实例重复窗口」）：
- single_event_ceiling_ms(config) 纯函数：(max_retries+1) x (jmap+telegram+llm) x 2
  (SAFETY)，并用 .max(SINGLE_EVENT_CEILING_FLOOR_MS=300_000) 兜底，
  零值配置不会把窗口缩到 legacy 常量之下。
- reclaim_idle_threshold_ms(config, count) 纯函数：count.max(1) x 单事件上限，
  再 .min(RECLAIM_IDLE_THRESHOLD_CAP_MS = 6h) 防误调把恢复拖到天级。
- read_batch 调用 self.get_outbound_config()（trait 方法，同实现内已有，未改签名），
  Ok 走推导值，Err 回退 count x 300_000（不破坏投递主流程、不传播 Redis 错误）。

既有闸门不动：notify.rs 投递前查 delivery:committed、60s delivery:inflight 在途租约、
retry_or_dlq 3 次。本次只修阈值本身，性质保持「永不丢、只可能重复；单实例不受影响」。

:356-364 那段注释改写为描述真实机制（旧文「~300s 上限」已不准确），
未写入任何未经测试证明的断言。

测试：3 个纯函数单测覆盖 —— 默认配置 (15+10+30)x4x2=440s >= 300s floor、
大超时配置阈值更大、零值配置不缩到 floor 之下、荒唐超时被封顶 6h、count=0 用 1 事件兜底。
GATE-P0 全绿：fmt --check、check --locked、clippy --locked --all-targets -D warnings、
test --locked → 55 passed / 0 failed / 1 ignored。

src/state.rs

@@ -60,6 +60,47 @@ impl Default for OutboundConfig {
     }
 }
 
+/// Legacy single-event ceiling. It is the floor the derived ceiling must clear
+/// and the fallback when the outbound config cannot be read.
+const SINGLE_EVENT_CEILING_FLOOR_MS: u64 = 300_000;
+
+/// Safety factor on the derived ceiling. Retries insert sleeps between
+/// attempts, and the ceiling bounds a window that must not be exceeded while
+/// the owning consumer is still alive.
+const SINGLE_EVENT_CEILING_SAFETY: u64 = 2;
+
+/// Upper bound on the XAUTOCLAIM idle window: a misconfigured timeout must not
+/// push multi-instance recovery out by days. Six hours keeps a crashed batch
+/// recoverable within the same working day.
+const RECLAIM_IDLE_THRESHOLD_CAP_MS: u64 = 6 * 60 * 60 * 1000;
+
+/// Worst-case wall clock for one event: every outbound call can burn its full
+/// timeout once per attempt and `send_text` retries up to `max_retries` more
+/// times, so the ceiling is
+/// `(max_retries + 1) * (jmap + telegram + llm) * SAFETY`, floored at the
+/// legacy constant so a zeroed-out config cannot shrink the window.
+fn single_event_ceiling_ms(config: &OutboundConfig) -> u64 {
+    let attempts = config.max_retries as u64 + 1;
+    let per_attempt = config
+        .jmap_timeout_ms
+        .saturating_add(config.telegram_timeout_ms)
+        .saturating_add(config.llm_timeout_ms);
+    per_attempt
+        .saturating_mul(attempts)
+        .saturating_mul(SINGLE_EVENT_CEILING_SAFETY)
+        .max(SINGLE_EVENT_CEILING_FLOOR_MS)
+}
+
+/// Idle window handed to `XAUTOCLAIM`: the worst-case *batch* duration, since a
+/// worker processes up to `count` events sequentially. Floored through
+/// `single_event_ceiling_ms` and capped so a bad config cannot stretch
+/// recovery into days. Only duplicate-on-multi-instance is at stake, never loss.
+fn reclaim_idle_threshold_ms(config: &OutboundConfig, count: usize) -> u64 {
+    (count.max(1) as u64)
+        .saturating_mul(single_event_ceiling_ms(config))
+        .min(RECLAIM_IDLE_THRESHOLD_CAP_MS)
+}
+
 #[async_trait]
 pub trait ReliableState: Send + Sync {
     /// Atomic SET NX EX claim for Telegram update or `(account,email)` dedup key.
@@ -360,13 +401,18 @@ impl ReliableState for RedisState {
             .await;
         // Recover messages left in the consumer group's PEL after a crash or
         // restart before reading new entries. The idle window has to clear the
-        // worst-case *batch* duration (a worker processes up to `count` events
-        // sequentially, each bounded by the ~300s single-event ceiling), else a
+        // worst-case *batch* duration: a worker processes up to `count` events
+        // sequentially, each bounded by the single-event ceiling derived from
+        // the live outbound config. If the window is shorter than that, a
         // second instance reclaims events that are still being processed and
         // delivers them twice (建议-6). Single-instance deployments are
         // unaffected; only duplicate-on-multi-instance is at stake, never loss.
-        const SINGLE_EVENT_CEILING_MS: u64 = 300_000;
-        let idle_threshold_ms = count.max(1) as u64 * SINGLE_EVENT_CEILING_MS;
+        let idle_threshold_ms = match self.get_outbound_config().await {
+            Ok(config) => reclaim_idle_threshold_ms(&config, count),
+            // A Redis error here must not break the delivery loop: fall back to
+            // the legacy constant instead of propagating the failure.
+            Err(_) => count.max(1) as u64 * SINGLE_EVENT_CEILING_FLOOR_MS,
+        };
         let reclaimed: redis::streams::StreamAutoClaimReply = redis::cmd("XAUTOCLAIM")
             .arg(stream)
             .arg(group)
@@ -1346,6 +1392,57 @@ mod tests {
         assert!(client.is_ok());
     }
 
+    #[test]
+    fn reclaim_idle_threshold_is_derived_from_runtime_config() {
+        // (15s + 10s + 30s) * (3 + 1) attempts * 2 safety = 440s per event.
+        let default = OutboundConfig::default();
+        assert_eq!(single_event_ceiling_ms(&default), 440_000);
+        assert!(reclaim_idle_threshold_ms(&default, 1) >= SINGLE_EVENT_CEILING_FLOOR_MS);
+        assert!(reclaim_idle_threshold_ms(&default, 16) > reclaim_idle_threshold_ms(&default, 8));
+
+        let slow = OutboundConfig {
+            jmap_timeout_ms: 60_000,
+            telegram_timeout_ms: 60_000,
+            llm_timeout_ms: 60_000,
+            max_retries: 4,
+        };
+        assert!(reclaim_idle_threshold_ms(&slow, 1) > reclaim_idle_threshold_ms(&default, 1));
+    }
+
+    #[test]
+    fn reclaim_idle_threshold_is_floored_and_capped() {
+        let zeroed = OutboundConfig {
+            jmap_timeout_ms: 0,
+            telegram_timeout_ms: 0,
+            llm_timeout_ms: 0,
+            max_retries: 0,
+        };
+        assert_eq!(
+            single_event_ceiling_ms(&zeroed),
+            SINGLE_EVENT_CEILING_FLOOR_MS
+        );
+
+        let absurd = OutboundConfig {
+            jmap_timeout_ms: 3_600_000,
+            telegram_timeout_ms: 3_600_000,
+            llm_timeout_ms: 3_600_000,
+            max_retries: 5,
+        };
+        assert_eq!(
+            reclaim_idle_threshold_ms(&absurd, 64),
+            RECLAIM_IDLE_THRESHOLD_CAP_MS
+        );
+    }
+
+    #[test]
+    fn reclaim_idle_threshold_ignores_empty_batches() {
+        let default = OutboundConfig::default();
+        assert_eq!(
+            reclaim_idle_threshold_ms(&default, 0),
+            single_event_ceiling_ms(&default)
+        );
+    }
+
     #[test]
     fn encrypted_config_roundtrip_and_tamper_fail_closed() {
         let key = [7_u8; 32];