feat(ECR-011): 昵称、首页贴士与档案 Self 唯一/合盘交叉校验

每账号仅一条 self（migration 40902）；合盘只选 TA；账号昵称可改；首页穿衣/颜色/养生贴士。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/internal/yijing/seed.go

@@ -0,0 +1,93 @@
+// Package yijing provides a deterministic hexagram seed from birth + local time.
+// It is a cultural rhythm seed for lifestyle tips — not fortune-telling.
+package yijing
+
+import (
+	"fmt"
+	"time"
+)
+
+// Context is the seed passed to LLM prompts.
+type Context struct {
+	GuaIndex   int    // 1..64
+	GuaName    string // short label
+	Line       int    // 1..6 changing line hint
+	DayPart    string // morning|noon|afternoon|evening|night
+	NowLocal   string
+	BirthDate  string
+	BirthTime  string
+}
+
+var guaNames = []string{
+	"乾", "坤", "屯", "蒙", "需", "讼", "师", "比",
+	"小畜", "履", "泰", "否", "同人", "大有", "谦", "豫",
+	"随", "蛊", "临", "观", "噬嗑", "贲", "剥", "复",
+	"无妄", "大畜", "颐", "大过", "坎", "离", "咸", "恒",
+	"遁", "大壮", "晋", "明夷", "家人", "睽", "蹇", "解",
+	"损", "益", "夬", "姤", "萃", "升", "困", "井",
+	"革", "鼎", "震", "艮", "渐", "归妹", "丰", "旅",
+	"巽", "兑", "涣", "节", "中孚", "小过", "既济", "未济",
+}
+
+// Seed builds hexagram context from birth date/time and now (Asia/Shanghai preferred).
+func Seed(birthDate string, birthTime *string, now time.Time) Context {
+	loc, err := time.LoadLocation("Asia/Shanghai")
+	if err != nil {
+		loc = time.FixedZone("CST", 8*3600)
+	}
+	now = now.In(loc)
+
+	bt := "12:00"
+	if birthTime != nil && *birthTime != "" {
+		bt = *birthTime
+	}
+
+	sum := hash(birthDate) + hash(bt) + hash(now.Format("2006-01-02")) + now.Hour()*17 + now.Minute()/10
+	gua := (sum % 64) + 1
+	line := (sum/7)%6 + 1
+	name := guaNames[gua-1]
+
+	return Context{
+		GuaIndex:  gua,
+		GuaName:   name,
+		Line:      line,
+		DayPart:   dayPart(now.Hour()),
+		NowLocal:  now.Format("2006-01-02 15:04"),
+		BirthDate: birthDate,
+		BirthTime: bt,
+	}
+}
+
+// PromptLine is a compact Chinese summary for the model.
+func (c Context) PromptLine() string {
+	return fmt.Sprintf(
+		"出生 %s %s；此刻 %s（时段 %s）；卦象种子：%s（第%d卦）· 动爻%d",
+		c.BirthDate, c.BirthTime, c.NowLocal, c.DayPart, c.GuaName, c.GuaIndex, c.Line,
+	)
+}
+
+func dayPart(h int) string {
+	switch {
+	case h < 6:
+		return "night"
+	case h < 11:
+		return "morning"
+	case h < 14:
+		return "noon"
+	case h < 18:
+		return "afternoon"
+	default:
+		return "evening"
+	}
+}
+
+func hash(s string) int {
+	n := 0
+	for i := 0; i < len(s); i++ {
+		n = n*131 + int(s[i])
+	}
+	if n < 0 {
+		n = -n
+	}
+	return n
+}

apps/api/internal/yijing/seed_test.go

@@ -0,0 +1,29 @@
+package yijing
+
+import (
+	"testing"
+	"time"
+)
+
+func TestSeedStableSameInputs(t *testing.T) {
+	bt := "10:30"
+	now := time.Date(2026, 8, 11, 19, 0, 0, 0, time.FixedZone("CST", 8*3600))
+	a := Seed("1990-05-12", &bt, now)
+	b := Seed("1990-05-12", &bt, now)
+	if a.GuaIndex != b.GuaIndex || a.GuaName != b.GuaName || a.Line != b.Line {
+		t.Fatalf("expected stable seed, got %+v vs %+v", a, b)
+	}
+	if a.GuaIndex < 1 || a.GuaIndex > 64 {
+		t.Fatalf("gua out of range: %d", a.GuaIndex)
+	}
+}
+
+func TestSeedChangesWithHour(t *testing.T) {
+	now1 := time.Date(2026, 8, 11, 9, 0, 0, 0, time.FixedZone("CST", 8*3600))
+	now2 := time.Date(2026, 8, 11, 18, 0, 0, 0, time.FixedZone("CST", 8*3600))
+	a := Seed("1990-05-12", nil, now1)
+	b := Seed("1990-05-12", nil, now2)
+	if a.DayPart == b.DayPart {
+		t.Fatalf("expected different day parts, both %s", a.DayPart)
+	}
+}