feat(tenant): guard numeric knowledge facts against silent contradiction

Ensure numeric facts present in retrieved knowledge (especially company
founding dates) cannot be silently contradicted in generated articles.

- Add a typed fact guard that extracts constraints (dates, experience
  years, etc.) from precise facts, detects source conflicts, and
  validates generated content before persistence with a bounded repair
  retry.
- Surface fact constraints through KnowledgeContext and render them as
  a canonical, non-derivable fact block in the knowledge prompt section.
- Tighten prompt intro lines to forbid rewriting, mixing old values,
  or deriving service years from founding dates.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/configs/prompts.yml

@@ -317,9 +317,10 @@ runtime:
     avoid_points: "需要规避"
     extra_requirements: "其他要求"
   knowledge_prompt_intro_lines:
-    - "以下为可参考的知识库内容，只用于补充事实背景、术语定义、产品信息或表达素材："
-    - "- 优先吸收并改写，但地址、电话、官网、邮箱、营业时间、日期，以及主营业务、经营范围、服务范围、核心产品等业务事实如需引用，必须严格依据原文，不得写成知识库里没有的业务内容。"
-    - "- 若知识库内容与用户明确输入冲突，以用户输入为准。"
+    - "以下知识库内容是事实来源，可用于补充事实背景、术语定义、产品信息或表达素材："
+    - "- 地址、电话、官网、邮箱、营业时间、成立/注册日期、年份、数量、面积、人数、比例、价格、认证编号，以及主营业务、经营范围、服务范围、核心产品等业务事实，只能严格依据已提供原文，不得改写数值、混用旧值、推测或补全。"
+    - "- 不得根据成立年份自行推算服务年限、行业经验或其他衍生数字；知识库未明确提供的数字型业务事实不要写。"
+    - "- 若临时输入与下方系统标记的规范事实冲突，以规范事实为准；需要更正时应先更新知识库。"
     - "- 信息不足时不要虚构事实。"
   knowledge_snippet_label_format: "知识片段 %d"
   knowledge_website_markdown: