Add value creation model and evidence-tier taxonomy

docs/business-model/business-requirements.md

@@ -73,6 +73,28 @@ Version 1 does not include:
 
 ## Updated Working Definition
 
-> "We continuously prevent silent customer loss for local businesses — making sure customers, search engines, and AI systems can find and accurately represent the business, and that customers can trust and act on what they find, often before the business would ever notice something was wrong."
+> "We continuously prevent silent customer loss for local businesses by making sure customers can find, trust, and engage the business, and that search engines and AI systems can find, understand, and accurately represent it, often before the business would ever notice something was wrong."
 
-*Working definition — not a final brand statement.*
+*Working definition — not a final brand statement.*
+
+---
+
+# Core Terminology
+
+## Silent Customer Loss
+
+Silent Customer Loss is the umbrella term for customer acquisition problems that occur without the business owner clearly seeing the loss.
+
+It includes both Customer Path Leakage and Discovery Failure.
+
+## Customer Path Leakage
+
+Customer Path Leakage occurs when a customer has interest or intent but fails to contact, book, visit, or otherwise engage the business because of digital friction.
+
+Examples include incorrect phone numbers, broken booking links, wrong hours, failed contact forms, confusing service information, or inaccurate listings.
+
+## Discovery Failure
+
+Discovery Failure occurs when a potential customer never meaningfully encounters the business because customers, search engines, or AI systems do not find, understand, surface, or accurately represent it.
+
+Examples include weak local visibility, incomplete entity signals, missing service clarity, absence from AI answer samples, poor structured information, or inconsistent citations.