fix(ai): subject 里塞了行数，每轮询一次就新建一个任务

生产上 trends 队列里积了 36 个任务，subject 是 2026-09-01:1033、:1039、
:1044……一路涨。这台账号当时正在补历史，get_summary 的行数每隔几分钟就变，
而我把 len(rows) 写进了 subject——subject 同时是缓存键和任务队列的键，一变
就是一条全新的任务，轮询几次就刷出十几条。

subject 该回答的是「这条解读是关于什么的」，不是「当时有多少行数据」。
数据变化本来就由 fingerprint 负责。

- trends 的 subject 改成快照日期；sleep 用配置的窗口常量而不是实际夜数
  （缺一晚也不该换键）；challenges 用固定键
- 加了不变量测试：补一天历史数据后 subject 不许变；任何 subject 段都不许
  长得像行数

顺带加一层兜底 jobs.supersede()：单实例 scope 只该有一个在跑的 subject，
队列里同 kind 的其它 pending 任务是关于已经不存在的快照的，跑完也没人看。
per_item 的 daily / activity 不受影响——它们本来就一天一条、一次运动一条。
兜底不是机制，机制是 subject 稳定；它存在只是因为这次 subject 不稳定，而
36 条任务堆在那里之前没人发现。

顺带按要求把 AiPanel 改成默认精简：只显示标题、来源和一句话结论，点「展开
详细」才出要点/建议/依据，可再收起——和今日晨报卡片一致。这些面板压在本来
就很密的图表页上面，全部默认展开会把真正的数据一次性挤到屏幕外。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/services/analysis.py

@@ -499,6 +499,8 @@ def get_scope_insight(user_id, scope, subject=None, refresh=False):
             insight, meta = cached
             return {"insight": insight, "context": context, "meta": meta}
 
+    if not scopes.SCOPES[scope].per_item:
+        jobs.supersede(user_id, scope, resolved)
     state = jobs.enqueue(user_id, scope, resolved, fingerprint,
                          jobs.PRIORITY_INTERACTIVE)
     return {
@@ -540,12 +542,15 @@ def prefetch_insights(user_id):
         if not built:
             continue
         resolved, context = built
+        if not scopes.SCOPES[scope].per_item:
+            jobs.supersede(user_id, scope, resolved)
         jobs.enqueue(user_id, scope, resolved, _context_fingerprint(context),
                      jobs.PRIORITY_PREFETCH)
         queued.append(scope)
 
     context = insights.build_context(user_id)
     if context:
+        jobs.supersede(user_id, "briefing", context["snapshotDate"])
         jobs.enqueue(user_id, "briefing", context["snapshotDate"],
                      _context_fingerprint(context), jobs.PRIORITY_PREFETCH)
         queued.append("briefing")

backend/services/jobs.py

@@ -150,6 +150,25 @@ def enqueue(user_id, kind, subject, fingerprint=None,
     return "pending"
 
 
+def supersede(user_id, kind, subject):
+    """Drop queued work of the same kind for a different subject.
+
+    A single-entry scope has one live subject; anything else queued under that
+    kind is about a snapshot that no longer exists, and running it would spend
+    a gateway call on an answer nothing will read.
+
+    This is a safety net, not the mechanism: subjects are supposed to be stable
+    (see scopes.py). It exists because they were not — a row count in the key
+    made every poll mint a new `trends` job, and production had 36 of them
+    queued before anyone noticed.
+    """
+    execute(
+        "DELETE FROM ai_jobs WHERE user_id = ? AND kind = ? AND subject != ? "
+        "AND status = 'pending'",
+        [user_id, kind, subject],
+    )
+
+
 def status_of(user_id, kind, subject):
     row = query_one("SELECT * FROM ai_jobs WHERE id = ?",
                     [job_id(user_id, kind, subject)])

backend/services/scopes.py

@@ -164,7 +164,9 @@ def build_sleep(user_id, subject=None):
                       + ("，偏低。" if deep < deep_low else "，达标。"),
         })
 
-    return f"{window[-1]['date']}:{len(window)}", {
+    # The configured window, not `len(window)`: a night missing from the record
+    # would otherwise change the key and queue a second job for the same screen.
+    return f"{window[-1]['date']}:{NIGHTS}", {
         "scope": "sleep",
         "label": "睡眠",
         "windowNights": len(window),
@@ -286,7 +288,7 @@ def build_trends(user_id, subject=None):
     if not highlights:
         highlights = [{"title": "整体", "detail": "各项指标长期走势平稳，无明显方向性变化。"}]
 
-    return f"{rows[-1]['date']}:{len(rows)}", {
+    return rows[-1]["date"], {
         "scope": "trends",
         "label": "长期趋势",
         "highlights": highlights,
@@ -492,7 +494,9 @@ def build_challenges(user_id, subject=None):
             "detail": f"{c.get('startDate')} ~ {c.get('endDate')}，状态 {c.get('status')}。",
         })
 
-    return f"{rows[0].get('startDate')}:{len(rows)}", {
+    # One entry per account: which challenges exist is what the fingerprint
+    # tracks, so the key does not need to encode how many there are.
+    return "all", {
         "scope": "challenges",
         "label": "挑战赛",
         "highlights": highlights,
@@ -559,13 +563,17 @@ def build_activity(user_id, subject=None):
 
 # --- registry ----------------------------------------------------------------
 class Scope:
-    __slots__ = ("name", "label", "build", "needs_subject")
+    __slots__ = ("name", "label", "build", "needs_subject", "per_item")
 
-    def __init__(self, name, label, build, needs_subject=False):
+    def __init__(self, name, label, build, needs_subject=False, per_item=False):
         self.name = name
         self.label = label
         self.build = build
         self.needs_subject = needs_subject
+        # `per_item` scopes legitimately have one entry per date or per
+        # session. Every other scope has exactly one live entry, so an older
+        # subject sitting in the queue is stale work — see `supersede`.
+        self.per_item = per_item
 
 
 SCOPES = {
@@ -574,12 +582,13 @@ SCOPES = {
         Scope("sleep", "睡眠", build_sleep),
         Scope("exercise", "运动", build_exercise),
         Scope("trends", "长期趋势", build_trends),
-        Scope("daily", "每日数据", build_daily),
+        Scope("daily", "每日数据", build_daily, per_item=True),
         Scope("body", "身体成分", build_body),
         Scope("race", "成绩预测", build_race),
         Scope("bodyAge", "身体年龄", build_body_age),
         Scope("challenges", "挑战赛", build_challenges),
-        Scope("activity", "运动详情", build_activity, needs_subject=True),
+        Scope("activity", "运动详情", build_activity, needs_subject=True,
+              per_item=True),
     )
 }
 

backend/tests/test_coach.py

@@ -981,3 +981,75 @@ class TestOutageRecovery:
         assert out["meta"]["pending"] is False
         assert out["meta"]["reason"], "the card should be able to say why"
         assert out["insight"]["headline"], "and still show the computed facts"
+
+
+class TestSubjectStability:
+    """The subject keys the cache *and* the job queue, so it must identify what
+    the insight is about — never how much data happened to be there.
+
+    A count in the key made every poll mint a fresh job: production
+    accumulated a dozen `trends` jobs in minutes, all for the same screen."""
+
+    def test_the_subject_does_not_move_when_the_data_grows(
+        self, db, user, seed_health
+    ):
+        seed_health([
+            {"date": f"2026-08-{d:02d}", "steps": 8000, "heart_rate": 60,
+             "hrv": 45, "sleep_duration": 7, "sleep_quality": 80, "stress": 30}
+            for d in range(1, 29)
+        ])
+        before = {
+            name: scopes.build(user["id"], name)[0]
+            for name in ("health", "sleep", "exercise", "trends")
+            if scopes.build(user["id"], name)
+        }
+
+        # A backfilled day, as a history sync would add: older than the newest,
+        # so what the screen is about has not changed.
+        seed_health([{"date": "2026-07-31", "steps": 7000, "heart_rate": 61,
+                      "hrv": 44, "sleep_duration": 7, "sleep_quality": 79,
+                      "stress": 31}])
+
+        after = {name: scopes.build(user["id"], name)[0] for name in before}
+        assert after == before
+
+    def test_no_subject_encodes_a_row_count(self, month):
+        for name in ("health", "sleep", "exercise", "trends", "challenges"):
+            built = scopes.build(month["id"], name)
+            if not built:
+                continue
+            subject = built[0]
+            # A count would grow without bound; a date or a window constant
+            # will not. This catches the shape of the mistake, not one instance.
+            for part in str(subject).split(":"):
+                assert not (part.isdigit() and int(part) > 400), \
+                    f"{name} subject {subject!r} looks like a row count"
+
+
+class TestSupersede:
+    def test_opening_a_screen_clears_queued_work_for_an_older_snapshot(
+        self, month, gateway
+    ):
+        jobs.enqueue(month["id"], "trends", "2026-08-01")
+        jobs.enqueue(month["id"], "trends", "2026-08-15")
+        analysis_svc.get_scope_insight(month["id"], "trends")
+        rows = analysis_svc.query_all(
+            "SELECT subject FROM ai_jobs WHERE kind = 'trends'")
+        assert len(rows) == 1, "only the current snapshot should be queued"
+
+    def test_per_item_screens_keep_one_job_each(self, month, gateway):
+        """每日 and 运动详情 legitimately have one entry per date / session."""
+        jobs.enqueue(month["id"], "daily", "2026-08-01")
+        jobs.enqueue(month["id"], "daily", "2026-08-02")
+        analysis_svc.get_scope_insight(month["id"], "daily", subject="2026-08-03")
+        rows = analysis_svc.query_all(
+            "SELECT subject FROM ai_jobs WHERE kind = 'daily'")
+        assert len(rows) == 3
+
+    def test_running_work_is_not_dropped_from_under_the_worker(self, month, gateway):
+        jobs.enqueue(month["id"], "trends", "2026-08-01")
+        jobs._claim_next()
+        analysis_svc.get_scope_insight(month["id"], "trends")
+        statuses = {r["subject"]: r["status"] for r in analysis_svc.query_all(
+            "SELECT subject, status FROM ai_jobs WHERE kind = 'trends'")}
+        assert statuses.get("2026-08-01") == "running"

client/src/components/AiPanel.css

@@ -85,6 +85,36 @@
   color: var(--text-primary);
 }
 
+.aip-detail {
+  border-top: 1px solid var(--border);
+  padding-top: 0.7rem;
+  margin-top: 0.5rem;
+  animation: aip-open 0.26s var(--ease) both;
+}
+
+@keyframes aip-open {
+  from { opacity: 0; transform: translateY(-4px); }
+  to { opacity: 1; transform: none; }
+}
+
+/* Full-width, at the foot of the card: the same affordance the 今日 briefing
+   uses, so the two read as one pattern rather than two. */
+.aip-toggle {
+  display: block;
+  width: 100%;
+  background: none;
+  border: none;
+  border-top: 1px solid var(--border);
+  margin-top: 0.5rem;
+  padding: 0.5rem 0 0.1rem;
+  font-size: 0.76rem;
+  font-weight: 600;
+  color: var(--text-muted);
+  cursor: pointer;
+}
+
+.aip-toggle:active { color: var(--accent); }
+
 .aip-point { margin-bottom: 0.55rem; }
 
 .aip-tag {

client/src/components/AiPanel.tsx

@@ -1,4 +1,4 @@
-import { useCallback } from 'react';
+import { useCallback, useState } from 'react';
 import {
   apiClient, InsightScope, InsightMeta, ScopeInsight,
 } from '../services/api';
@@ -48,6 +48,13 @@ function Badge({ meta }: { meta: InsightMeta }) {
  * screen — which opening the screen moves to the front of.
  */
 function AiPanel({ scope, subject, title = 'AI 解读' }: Props) {
+  /* Collapsed by default, the same as the 今日 briefing card. These panels sit
+     on top of screens that are already dense with charts; opening every one of
+     them by default would push the actual data below the fold on every screen
+     at once. The conclusion is always visible — it is the detail behind it
+     that waits to be asked for. */
+  const [open, setOpen] = useState(false);
+
   const load = useCallback(async () => {
     const resp = await apiClient.getInsight(scope, { subject });
     return { data: resp.insight, meta: resp.meta };
@@ -71,6 +78,8 @@ function AiPanel({ scope, subject, title = 'AI 解读' }: Props) {
 
       {data.headline && <p className="aip-headline">{data.headline}</p>}
 
+      {open && (
+        <div className="aip-detail">
           {data.points.map((p) => (
             <div className="aip-point" key={p.title + p.detail}>
               <span className="aip-tag">{p.title}</span>
@@ -92,6 +101,19 @@ function AiPanel({ scope, subject, title = 'AI 解读' }: Props) {
             </button>
             <span>{CONFIDENCE_LABEL[data.confidence]}</span>
           </div>
+        </div>
+      )}
+
+      {/* Nothing to expand into when the reading is a headline on its own. */}
+      {(!!data.points.length || !!data.actions.length || !!data.caution) && (
+        <button
+          className="aip-toggle"
+          onClick={() => setOpen((v) => !v)}
+          aria-expanded={open}
+        >
+          {open ? '收起' : `展开详细（${data.points.length} 项）`}
+        </button>
+      )}
     </section>
   );
 }