Fix E2E test gaps and add comprehensive E2E + parity test suites

- Fix pull consumer fetch: send original stream subject in HMSG (not inbox)
  so NATS client distinguishes data messages from control messages
- Fix MaxAge expiry: add background timer in StreamManager for periodic pruning
- Fix JetStream wire format: Go-compatible anonymous objects with string enums,
  proper offset-based pagination for stream/consumer list APIs
- Add 42 E2E black-box tests (core messaging, auth, TLS, accounts, JetStream)
- Add ~1000 parity tests across all subsystems (gaps closure)
- Update gap inventory docs to reflect implementation status

src/NATS.Server/Configuration/NatsConfToken.cs

@@ -1,5 +1,7 @@
 // Port of Go conf/lex.go token types.
 
+using System.Text.Json;
+
 namespace NATS.Server.Configuration;
 
 public enum TokenType
@@ -7,6 +9,7 @@ public enum TokenType
     Error,
     Eof,
     Key,
+    Text,
     String,
     Bool,
     Integer,
@@ -22,3 +25,34 @@ public enum TokenType
 }
 
 public readonly record struct Token(TokenType Type, string Value, int Line, int Position);
+
+/// <summary>
+/// Pedantic token wrapper matching Go conf/parse.go token accessors.
+/// </summary>
+public sealed class PedanticToken
+{
+    private readonly Token _item;
+    private readonly object? _value;
+    private readonly bool _usedVariable;
+    private readonly string _sourceFile;
+
+    public PedanticToken(Token item, object? value = null, bool usedVariable = false, string sourceFile = "")
+    {
+        _item = item;
+        _value = value;
+        _usedVariable = usedVariable;
+        _sourceFile = sourceFile ?? string.Empty;
+    }
+
+    public string MarshalJson() => JsonSerializer.Serialize(Value());
+
+    public object? Value() => _value ?? _item.Value;
+
+    public int Line() => _item.Line;
+
+    public bool IsUsedVariable() => _usedVariable;
+
+    public string SourceFile() => _sourceFile;
+
+    public int Position() => _item.Position;
+}