Move inline code examples out of normative contracts

identifier-normalization, no-hardcoded-vendors,
vendor-installer-verification, and build-version-display follow the
go-database split: rules in contract.md, snippets in README.md. Routed
contract reads get cheaper; examples stay available on demand. Lint now
also rejects stale kit/patterns references.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

rules/patterns/identifier-normalization/README.md

@@ -0,0 +1,54 @@
+# Identifier Normalization Pattern Notes
+
+This file keeps examples. The normative rules live in `contract.md`.
+
+## Go — сравнение
+
+```go
+import "strings"
+
+func SameIdentifier(a, b string) bool {
+    return strings.EqualFold(a, b)
+}
+```
+
+## Go — дедупликация
+
+```go
+func deduplicateBySerial(items []Device) []Device {
+    seen := make(map[string]struct{})
+    result := items[:0]
+    for _, item := range items {
+        key := strings.ToLower(item.SerialNumber)
+        if _, exists := seen[key]; !exists {
+            seen[key] = struct{}{}
+            result = append(result, item)
+        }
+    }
+    return result
+}
+```
+
+## SQL — поиск и уникальность
+
+Поиск:
+
+```sql
+SELECT * FROM devices WHERE LOWER(serial_number) = LOWER(?);
+```
+
+Уникальный индекс (MySQL / MariaDB):
+
+```sql
+-- Collation ci обеспечивает case-insensitive уникальность
+ALTER TABLE devices MODIFY serial_number VARCHAR(255)
+    CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
+
+ALTER TABLE devices ADD UNIQUE INDEX uniq_serial (serial_number);
+```
+
+SQLite:
+
+```sql
+CREATE UNIQUE INDEX uniq_serial ON devices (LOWER(serial_number));
+```