feat(shared): add case-insensitive utilities for agent name matching

Add findCaseInsensitive, includesCaseInsensitive, findByNameCaseInsensitive,
and equalsIgnoreCase functions for consistent case-insensitive lookups across
the codebase. Enables 'Oracle', 'oracle', 'ORACLE' to work interchangeably.

src/shared/case-insensitive.ts

@@ -0,0 +1,46 @@
+/**
+ * Case-insensitive lookup and comparison utilities for agent/config names.
+ * Used throughout the codebase to allow "Oracle", "oracle", "ORACLE" to work the same.
+ */
+
+/**
+ * Find a value in an object using case-insensitive key matching.
+ * First tries exact match, then falls back to lowercase comparison.
+ */
+export function findCaseInsensitive<T>(obj: Record<string, T> | undefined, key: string): T | undefined {
+  if (!obj) return undefined
+  const exactMatch = obj[key]
+  if (exactMatch !== undefined) return exactMatch
+  const lowerKey = key.toLowerCase()
+  for (const [k, v] of Object.entries(obj)) {
+    if (k.toLowerCase() === lowerKey) return v
+  }
+  return undefined
+}
+
+/**
+ * Check if an array includes a value using case-insensitive comparison.
+ */
+export function includesCaseInsensitive(arr: string[], value: string): boolean {
+  const lowerValue = value.toLowerCase()
+  return arr.some((item) => item.toLowerCase() === lowerValue)
+}
+
+/**
+ * Find an element in array using case-insensitive name matching.
+ * Useful for finding agents/categories by name.
+ */
+export function findByNameCaseInsensitive<T extends { name: string }>(
+  arr: T[],
+  name: string
+): T | undefined {
+  const lowerName = name.toLowerCase()
+  return arr.find((item) => item.name.toLowerCase() === lowerName)
+}
+
+/**
+ * Check if two strings are equal (case-insensitive).
+ */
+export function equalsIgnoreCase(a: string, b: string): boolean {
+  return a.toLowerCase() === b.toLowerCase()
+}