feat(timeline): merge bp.systolic + bp.diastolic into single entry

- TimelineEntry.from(indicators:) 批处理:找 bp.systolic 配对同 capturedAt
  (±5s)的 bp.diastolic,合并成 '血压 120/80 mmHg' 一行
- 未配对的 systolic 单独退回 from(indicator:)
- 非 bp.* series 不动
- ArchiveListView + HomeView 改用 from(indicators:) 批处理
- 6 个新测试覆盖配对/未配对/异常标记/非 bp 不动/不同时间不合并

康康Tests/TimelineEntryBPMergeTests.swift

@@ -0,0 +1,116 @@
+import Testing
+import SwiftData
+import Foundation
+@testable import 康康
+
+@MainActor
+struct TimelineEntryBPMergeTests {
+
+    private func makeContext() throws -> ModelContext {
+        let schema = Schema([Indicator.self])
+        let config = ModelConfiguration(schema: schema, isStoredInMemoryOnly: true)
+        return ModelContext(try ModelContainer(for: schema, configurations: [config]))
+    }
+
+    private func bp(sys: Int, dia: Int, at: Date, in ctx: ModelContext) -> (Indicator, Indicator) {
+        let s = Indicator(name: "收缩压", value: "\(sys)", unit: "mmHg",
+                          range: "90-140", status: .normal,
+                          capturedAt: at, pinned: true, seriesKey: "bp.systolic")
+        let d = Indicator(name: "舒张压", value: "\(dia)", unit: "mmHg",
+                          range: "60-90", status: .normal,
+                          capturedAt: at, pinned: true, seriesKey: "bp.diastolic")
+        ctx.insert(s); ctx.insert(d)
+        return (s, d)
+    }
+
+    @Test func bpPairAtSameTimeMergesIntoSingleEntry() throws {
+        let ctx = try makeContext()
+        let now = Date(timeIntervalSince1970: 1_716_000_000)
+        _ = bp(sys: 120, dia: 80, at: now, in: ctx)
+        try ctx.save()
+
+        let all = try ctx.fetch(FetchDescriptor<Indicator>())
+        let entries = TimelineEntry.from(indicators: all)
+
+        #expect(entries.count == 1)
+        let e = try #require(entries.first)
+        #expect(e.title == "血压")
+        #expect(e.trailing?.contains("120/80") == true)
+        #expect(e.trailingIsAlert == false)
+    }
+
+    @Test func bpPairWithAbnormalSystolicMarksAlert() throws {
+        let ctx = try makeContext()
+        let now = Date()
+        let (s, _) = bp(sys: 150, dia: 80, at: now, in: ctx)
+        s.statusRaw = IndicatorStatus.high.rawValue
+        try ctx.save()
+
+        let all = try ctx.fetch(FetchDescriptor<Indicator>())
+        let entries = TimelineEntry.from(indicators: all)
+        #expect(entries.count == 1)
+        #expect(entries.first?.trailingIsAlert == true)
+        #expect(entries.first?.trailing?.contains("↑") == true)
+    }
+
+    @Test func nonBPSeriesStayAsSeparateEntries() throws {
+        let ctx = try makeContext()
+        let now = Date()
+        let glu = Indicator(name: "空腹血糖", value: "5.4", unit: "mmol/L",
+                            range: "3.9-6.1", status: .normal,
+                            capturedAt: now, pinned: true, seriesKey: "glucose.fasting")
+        let weight = Indicator(name: "体重", value: "68", unit: "kg",
+                               range: "", status: .normal,
+                               capturedAt: now, pinned: true, seriesKey: "weight")
+        ctx.insert(glu); ctx.insert(weight)
+        try ctx.save()
+
+        let all = try ctx.fetch(FetchDescriptor<Indicator>())
+        let entries = TimelineEntry.from(indicators: all)
+        #expect(entries.count == 2)
+        #expect(entries.contains { $0.title == "空腹血糖" })
+        #expect(entries.contains { $0.title == "体重" })
+    }
+
+    @Test func bpAtDifferentTimesDoNotMerge() throws {
+        let ctx = try makeContext()
+        let t1 = Date(timeIntervalSince1970: 1_716_000_000)
+        let t2 = t1.addingTimeInterval(3600)  // 1 小时后
+        _ = bp(sys: 120, dia: 80, at: t1, in: ctx)
+        _ = bp(sys: 130, dia: 85, at: t2, in: ctx)
+        try ctx.save()
+
+        let all = try ctx.fetch(FetchDescriptor<Indicator>())
+        let entries = TimelineEntry.from(indicators: all)
+        #expect(entries.count == 2)
+    }
+
+    @Test func unpairedSystolicFallsBackToSingleEntry() throws {
+        let ctx = try makeContext()
+        let s = Indicator(name: "收缩压", value: "120", unit: "mmHg",
+                          range: "90-140", status: .normal,
+                          capturedAt: .now, pinned: true, seriesKey: "bp.systolic")
+        ctx.insert(s)
+        try ctx.save()
+
+        let all = try ctx.fetch(FetchDescriptor<Indicator>())
+        let entries = TimelineEntry.from(indicators: all)
+        // 没找到 diastolic 配对,落到单 from(indicator:),显示 "收缩压"
+        #expect(entries.count == 1)
+        #expect(entries.first?.title == "收缩压")
+    }
+
+    @Test func freeformIndicatorWithoutSeriesKeyShowsAsItself() throws {
+        let ctx = try makeContext()
+        let i = Indicator(name: "ALT", value: "32", unit: "U/L",
+                          range: "9-50", status: .normal,
+                          capturedAt: .now)
+        ctx.insert(i)
+        try ctx.save()
+
+        let all = try ctx.fetch(FetchDescriptor<Indicator>())
+        let entries = TimelineEntry.from(indicators: all)
+        #expect(entries.count == 1)
+        #expect(entries.first?.title == "ALT")
+    }
+}