fix: remove resumption-token length cap

Author: mattrmc1

lib/sdk/server-ai/src/main/java/com/launchdarkly/sdk/server/ai/internal/ResumptionTokens.java

@@ -14,7 +14,6 @@
  * This class is an internal implementation detail and is not part of the supported API.
  */
 final class ResumptionTokens {
-  private static final int MAX_TOKEN_LENGTH = 4096;
   private static final Base64.Encoder ENCODER = Base64.getUrlEncoder().withoutPadding();
   private static final Base64.Decoder DECODER = Base64.getUrlDecoder();
 
@@ -55,15 +54,12 @@ static String encode(String runId, String configKey, String variationKey,
    *
    * @param token the URL-safe Base64 token
    * @return the decoded fields
-   * @throws IllegalArgumentException if the token is malformed, oversized, or missing required fields
+   * @throws IllegalArgumentException if the token is malformed or missing required fields
    */
   static Decoded decode(String token) {
     if (token == null) {
       throw new IllegalArgumentException("Resumption token must not be null");
     }
-    if (token.length() > MAX_TOKEN_LENGTH) {
-      throw new IllegalArgumentException("Resumption token exceeds maximum length of " + MAX_TOKEN_LENGTH + " characters");
-    }
 
     String json;
     try {

lib/sdk/server-ai/src/test/java/com/launchdarkly/sdk/server/ai/internal/ResumptionTokensTest.java

@@ -86,23 +86,23 @@ public void versionIsPreservedOnRoundTrip() {
     assertThat(ResumptionTokens.decode(token).getVersion(), is(1));
   }
 
+  // ---- large keys -----------------------------------------------------------
+
+  @Test
+  public void roundTripsLongKeys() {
+    String key = new String(new char[5000]).replace('\0', 'a');
+    String token = ResumptionTokens.encode("run", key, null, 1, null);
+    ResumptionTokens.Decoded d = ResumptionTokens.decode(token);
+    assertThat(d.getConfigKey(), is(key));
+  }
+
   // ---- decode error handling ------------------------------------------------
 
   @Test(expected = IllegalArgumentException.class)
   public void decodeRejectsNull() {
     ResumptionTokens.decode(null);
   }
 
-  @Test(expected = IllegalArgumentException.class)
-  public void decodeRejectsOversizedToken() {
-    // Build a token larger than 4096 bytes
-    String largeValue = new String(new char[5000]).replace('\0', 'x');
-    String json = "{\"runId\":\"" + largeValue + "\",\"configKey\":\"c\",\"version\":1}";
-    String token = java.util.Base64.getUrlEncoder().withoutPadding()
-        .encodeToString(json.getBytes(java.nio.charset.StandardCharsets.UTF_8));
-    ResumptionTokens.decode(token);
-  }
-
   @Test(expected = IllegalArgumentException.class)
   public void decodeRejectsInvalidBase64() {
     ResumptionTokens.decode("not-valid-base64!!!!");