fix(server): support cypher bound queries safely

[imbajin]

Purpose of the PR

Cypher POST previously accepted only raw query text, missing parameters could silently become null,
and a failed write could leave changes visible after later reads. This change accepts validated JSON
bindings and rolls back traversal failures on the thread that owns the transaction.

This is a standalone change on current Apache master, which now includes the Java 17 / TinkerPop 3.8.1
upgrade. The translator remains translation:1.0.4. Related organization PR:
hugegraph#238. Paired website documentation:
apache/hugegraph-doc#499; coordinate its merge with this change.

Main Changes

• Preserve GET and legacy raw POST under application/json; accept
  { "cypher": "RETURN $name AS name", "parameters": { "name": "marko" } }.
  Reject malformed/non-object JSON and unsupported text/plain requests.
• Keep values separate from query text, reject missing bindings and the translator's reserved null
  marker, and retain binding type/count validation. Real null and parameter names such as id remain valid.
• Commit before the terminal success response; roll back and close the traversal on its execution
  thread after failures, including Java errors, and send a terminal failure response.
• Preserve the merged REST client's native charset handling while recognizing JSON media types with
  charset parameters. Release Gremlin HTTP requests exactly once on success and error paths.

query + parameters -> validation -> traversal worker
                                   success: commit -> response
                                   failure: rollback -> error response

Verifying these changes

• Trivial rework / code cleanup without any test coverage. (No Need)
• Already covered by existing tests.
• Need tests and can be verified as follows:
  • Java 17, TinkerPop 3.8.1, translator 1.0.4, and a live RocksDB-backed Server.
  • Cypher request, binding, regex, routing and write/rollback regression tests, including native readback.
  • Real-executor fatal-error response/rollback tests; Gremlin HTTP request ownership and auth-context tests.
  • REST JSON/map charset tests with UTF-8/UTF-16, gzip and an ASCII-default JVM.
  • Related Gremlin and Login API regressions, formatting, root clean compile and reactor installation.

All selected regressions, formatting, root clean compile and installation passed. Gremlin API retained
one existing non-shared-backend skip; Cypher tests had no skips. Advanced Cypher constructs, HStore, Bolt,
cross-request transactions and performance remain outside the verified scope. The compatibility note
also records the translator's reserved null-marker limitation for literals and stored properties.

Does this PR potentially affect the following parts?

• Dependencies
• Modify configurations
• The public API
• Other affects
• Nope

Documentation Status

• Doc - TODO: required documentation is pending; complete it before merging.
• Doc - Done: documentation is included here or linked below.
• Doc - No Need: no user-visible documentation is affected.

Repository documentation: docs/cypher-compatibility.md, the Server README, Commons README and
docs/upgrade-tinkerpop-3.8.md. Paired website PR: apache/hugegraph-doc#499.

[codecov]

Codecov Report

❌ Patch coverage is 72.29730% with 41 lines in your changes missing coverage. Please review.
✅ Project coverage is 41.76%. Comparing base (e62c961) to head (fd8f4a6).

Files with missing lines	Patch %	Lines
...apache/hugegraph/opencypher/CypherOpProcessor.java	64.55%	21 Missing and 7 partials ⚠️
.../org/apache/hugegraph/api/cypher/CypherClient.java	61.53%	1 Missing and 4 partials ⚠️
...ava/org/apache/hugegraph/api/cypher/CypherAPI.java	90.32%	0 Missing and 3 partials ⚠️
...he/hugegraph/server/HttpGremlinRequestHandler.java	72.72%	2 Missing and 1 partial ⚠️
...rg/apache/hugegraph/auth/ContextGremlinServer.java	75.00%	0 Missing and 1 partial ⚠️
...ugegraph/server/HugeGraphWsAndHttpChannelizer.java	90.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3289      +/-   ##
============================================
+ Coverage     41.19%   41.76%   +0.56%     
- Complexity     6773     6924     +151     
============================================
  Files           766      768       +2     
  Lines         66086    66205     +119     
  Branches       8773     8798      +25     
============================================
+ Hits          27225    27651     +426     
+ Misses        35818    35435     -383     
- Partials       3043     3119      +76     

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