feat(knowledge): broaden context resolution and prompt query

- Walk knowledge group children recursively so selecting a parent group
  pulls snippets from its descendants too.
- Filter knowledge items to status='completed' across the prompt and
  active-snippet queries to avoid leaking in-progress documents.
- Dedupe vector candidates by point id and normalized text, then pick
  rerank+vector results with a per-item cap so prompts stay diverse.
- Tag each rendered snippet with a [Kn] reference id for prompt citing.
- Build the rule knowledge query from task params (title/keywords/etc.)
  before falling back to rule prompt content so retrieval matches the
  user's actual ask.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/tenant/app/knowledge_prompt_test.go

@@ -3,6 +3,8 @@ package app
 import (
 	"strings"
 	"testing"
+
+	"github.com/geo-platform/tenant-api/internal/shared/retrieval"
 )
 
 func TestExtractKnowledgePreciseFactsKeepsAddressAndContactLines(t *testing.T) {
@@ -43,6 +45,7 @@ func TestRenderPromptSectionIncludesPreciseFactsAndSourceURI(t *testing.T) {
 	for _, expected := range []string{
 		"以下为必须严格按原文保留的高精度事实",
 		"- 门店信息 / 合肥门店：地址：合肥市蜀山区望江西路 123 号",
+		"1. [K1] 门店信息 / 合肥门店",
 		"来源链接: https://example.com/store",
 		"这里是一段门店介绍。",
 	} {
@@ -93,6 +96,64 @@ func TestExtractKnowledgePreciseFactsKeepsBusinessScopeSection(t *testing.T) {
 	}
 }
 
+func TestKnowledgeSnippetsFromSearchPointsSkipsMissingTextAndDedupes(t *testing.T) {
+	snippets := dedupeKnowledgeSearchCandidates(knowledgeSnippetsFromSearchPoints([]retrieval.SearchPoint{
+		{
+			ID:    "point-1",
+			Score: 0.91,
+			Payload: map[string]any{
+				"group_id":   int64(10),
+				"group_name": "产品资料",
+				"item_id":    int64(100),
+				"item_name":  "旗舰款",
+				"text":       "  支持全屋定制方案  ",
+			},
+		},
+		{
+			ID: "point-2",
+			Payload: map[string]any{
+				"text": "支持全屋定制方案",
+			},
+		},
+		{
+			ID:      "point-3",
+			Payload: map[string]any{},
+		},
+	}))
+
+	if len(snippets) != 1 {
+		t.Fatalf("deduped snippets length = %d, want 1: %#v", len(snippets), snippets)
+	}
+	if snippets[0].Text != "支持全屋定制方案" {
+		t.Fatalf("snippet text = %q, want trimmed text", snippets[0].Text)
+	}
+}
+
+func TestSelectKnowledgeRerankedSnippetsFillsAndDiversifiesResults(t *testing.T) {
+	candidates := []KnowledgeSnippet{
+		{PointID: "p1", KnowledgeItemID: 1, Text: "同一文档片段 1", Score: 0.90},
+		{PointID: "p2", KnowledgeItemID: 1, Text: "同一文档片段 2", Score: 0.89},
+		{PointID: "p3", KnowledgeItemID: 1, Text: "同一文档片段 3", Score: 0.88},
+		{PointID: "p4", KnowledgeItemID: 2, Text: "第二文档片段", Score: 0.80},
+		{PointID: "p5", KnowledgeItemID: 3, Text: "第三文档片段", Score: 0.70},
+	}
+
+	selected := selectKnowledgeRerankedSnippets(candidates, []retrieval.RerankResult{
+		{Index: 2, RelevanceScore: 0.99},
+		{Index: 99, RelevanceScore: 1},
+	}, 4)
+
+	if len(selected) != 4 {
+		t.Fatalf("selected length = %d, want 4: %#v", len(selected), selected)
+	}
+	if selected[0].PointID != "p3" || selected[0].Score != 0.99 {
+		t.Fatalf("selected[0] = %#v, want reranked p3 with rerank score", selected[0])
+	}
+	if selected[1].PointID != "p1" || selected[2].PointID != "p4" || selected[3].PointID != "p5" {
+		t.Fatalf("selected order = %#v, want reranked result filled with diverse vector candidates", selected)
+	}
+}
+
 func containsExactString(items []string, target string) bool {
 	for _, item := range items {
 		if item == target {