[WIP] Fix CTest failure of RealIpResolver on s390x

[Copilot]

Fix RealIpResolver test failure on s390x (big-endian architecture)

Root Cause Analysis:
The test shows "1.0.0.127" == "127.0.0.1" - bytes are reversed on s390x (big-endian) but not on x86_64/aarch64 (little-endian).

The issue is in RealIpResolver::CIDR::CIDR constructor and matchCidr:

• htonl() converts host→network byte order
• On little-endian: swaps bytes (correct)
• On big-endian: no-op (incorrect when mixing with network byte order values)
• ipNetEndian() returns network byte order (always big-endian)
• Mixing htonl() with ipNetEndian() causes endianness bugs on big-endian systems

Solution:
Replace htonl() with direct network byte order constant or ensure consistent byte ordering across all architectures.

Plan:

• Understand the codebase structure and build system
• Identify the exact fix needed in RealIpResolver.cc
• Implement the fix to handle endianness correctly
• Build and run the RealIpResolver test to verify the fix
• Request code review
• Run security checks

Original prompt

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This section details on the original issue you should resolve

<issue_title>CTest of RealIpResolver failed on s390x</issue_title>
<issue_description>Describe the bug

CTest of RealIpResolver failed on Fedora s390x, but passed on other architecture, like x86_64, aarch64.

+ /usr/bin/ctest --test-dir redhat-linux-build --output-on-failure --force-new-ctest-process -j2
Internal ctest changing into directory: /builddir/build/BUILD/drogon-1.9.11_20251226git39eb780-build/drogon-39eb78089d3c1f7d7024dd5053356d14409655f9/redhat-linux-build
Test project /builddir/build/BUILD/drogon-1.9.11_20251226git39eb780-build/drogon-39eb78089d3c1f7d7024dd5053356d14409655f9/redhat-linux-build
      Start  1: TestFrameworkSelfTest
      Start  2: Base64
 1/47 Test  drogonframework/drogon#1: TestFrameworkSelfTest ................   Passed    0.01 sec
      Start  3: URLCodec
 2/47 Test  drogonframework/drogon#2: Base64 ...............................   Passed    0.01 sec
      Start  4: Gzip
 3/47 Test  drogonframework/drogon#3: URLCodec .............................   Passed    0.01 sec
      Start  5: HttpViewData
 4/47 Test  drogonframework/drogon#4: Gzip .................................   Passed    0.01 sec
      Start  6: CookieTest
 5/47 Test  drogonframework/drogon#5: HttpViewData .........................   Passed    0.01 sec
      Start  7: ClassName
 6/47 Test  drogonframework/drogon#6: CookieTest ...........................   Passed    0.01 sec
      Start  8: HttpDate
 7/47 Test  drogonframework/drogon#7: ClassName ............................   Passed    0.01 sec
      Start  9: HttpHeaderRequest
 8/47 Test  drogonframework/drogon#8: HttpDate .............................   Passed    0.01 sec
      Start 10: HttpHeaderResponse
 9/47 Test  drogonframework/drogon#9: HttpHeaderRequest ....................   Passed    0.01 sec
      Start 11: ResponseSetCustomContentTypeString
10/47 Test drogonframework/drogon#10: HttpHeaderResponse ...................   Passed    0.01 sec
      Start 12: ResquestSetCustomContentTypeString
11/47 Test drogonframework/drogon#11: ResponseSetCustomContentTypeString ...   Passed    0.01 sec
      Start 13: Md5Test
12/47 Test drogonframework/drogon#12: ResquestSetCustomContentTypeString ...   Passed    0.01 sec
      Start 14: MsgBufferTest
13/47 Test drogonframework/drogon#13: Md5Test ..............................   Passed    0.01 sec
      Start 15: OStringStreamTest
14/47 Test drogonframework/drogon#14: MsgBufferTest ........................   Passed    0.01 sec
      Start 16: PubSubServiceTest
15/47 Test drogonframework/drogon#15: OStringStreamTest ....................   Passed    0.01 sec
      Start 17: SHA1Test
16/47 Test drogonframework/drogon#16: PubSubServiceTest ....................   Passed    0.01 sec
      Start 18: ExtensionTest
17/47 Test drogonframework/drogon#17: SHA1Test .............................   Passed    0.01 sec
      Start 19: ContentTypeTest
18/47 Test drogonframework/drogon#18: ExtensionTest ........................   Passed    0.01 sec
      Start 20: FileTypeTest
19/47 Test drogonframework/drogon#19: ContentTypeTest ......................   Passed    0.01 sec
      Start 21: DrObjectCreationTest
20/47 Test drogonframework/drogon#20: FileTypeTest .........................   Passed    0.01 sec
      Start 22: DrObjectNamespaceTest
21/47 Test drogonframework/drogon#21: DrObjectCreationTest .................   Passed    0.01 sec
      Start 23: IsAutoCreationClassTest
22/47 Test drogonframework/drogon#22: DrObjectNamespaceTest ................   Passed    0.01 sec
      Start 24: HttpFullDateTest
23/47 Test drogonframework/drogon#23: IsAutoCreationClassTest ..............   Passed    0.01 sec
      Start 25: MainLoopTest
24/47 Test drogonframework/drogon#24: HttpFullDateTest .....................   Passed    0.01 sec
      Start 26: CacheMapTest
25/47 Test drogonframework/drogon#25: MainLoopTest .........................   Passed    0.01 sec
      Start 27: StringOpsTest
26/47 Test drogonframework/drogon#27: StringOpsTest ........................   Passed    0.01 sec
      Start 28: ControllerCreation
27/47 Test drogonframework/drogon#28: ControllerCreation ...................   Passed    0.01 sec
      Start 29: MultiPartParser
28/47 Test drogonframework/drogon#29: MultiPartParser ......................   Passed    0.01 sec
      Start 30: MultiPartStreamParser
29/47 Test drogonframework/drogon#30: MultiPartStreamParser ................   Passed    0.01 sec
      Start 31: SlashRemoverTest
30/47 Test drogonframework/drogon#31: SlashRemoverTest .....................   Passed    0.01 sec
      Start 32: CanConvertFromStringStream
31/47 Test drogonframework/drogon#32: CanConvertFromStringStream ...........   Passed    0.01 sec
      Start 33: CanConstructFromString
32/47 Test drogonframework/drogon#33: CanConstructFromString ...............   Passed    0.01 sec
      Start 34: CanConvertFromString
33/47 Test drogonframework/drogon#34: CanConvertFr...

</details>



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- Fixes drogonframework/drogon#2436

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