fix(knowledgebase): parsing for knowledge

lib/core/utils/json_parsing.dart

@@ -0,0 +1,53 @@
+/// Utilities for parsing JSON values with graceful fallbacks.
+///
+/// These helpers handle various API response formats and provide defensive
+/// parsing to avoid crashes from malformed data.
+library;
+
+/// Parses a DateTime from various formats.
+///
+/// Handles:
+/// - `DateTime` objects (returned as-is)
+/// - ISO 8601 strings (parsed)
+/// - Unix timestamps as integers (assumed to be in seconds)
+/// - `null` or invalid values (returns [DateTime.now])
+DateTime parseDateTime(Object? value) {
+  if (value == null) {
+    return DateTime.now();
+  }
+  if (value is DateTime) {
+    return value;
+  }
+  if (value is String) {
+    // Use tryParse to avoid FormatException on malformed strings
+    return DateTime.tryParse(value) ?? DateTime.now();
+  }
+  if (value is int) {
+    // Assume Unix timestamp in seconds
+    return DateTime.fromMillisecondsSinceEpoch(value * 1000);
+  }
+  return DateTime.now();
+}
+
+/// Parses a nullable DateTime from various formats.
+///
+/// Returns `null` if the input is `null`, otherwise delegates to [parseDateTime].
+DateTime? parseDateTimeOrNull(Object? value) {
+  if (value == null) return null;
+  return parseDateTime(value);
+}
+
+/// Parses an int from various formats.
+///
+/// Handles:
+/// - `int` values (returned as-is)
+/// - `num` values (converted to int)
+/// - String values (parsed with [int.tryParse])
+/// - `null` or invalid values (returns `null`)
+int? parseInt(Object? value) {
+  if (value == null) return null;
+  if (value is int) return value;
+  if (value is num) return value.toInt();
+  if (value is String) return int.tryParse(value);
+  return null;
+}