e2e: port batch subcommand to all five client CLIs

scripts/run-client-e2e-tests.ps1 expects each language CLI to expose a
`batch` subcommand that reads command lines from stdin, runs each
through the normal subcommand dispatch, writes the JSON result, then
a sentinel line `__MXGW_BATCH_EOR__`. The implementation lived on a
divergent branch (commit 6126099) that was never merged into main —
this commit ports the same protocol to HEAD's renamed CLIs so the
existing matrix script runs end-to-end.

The protocol:
  - one line of stdin = one full CLI invocation
  - successful output → stdout, then __MXGW_BATCH_EOR__
  - failure → {"error":"...","type":"error"} JSON on stdout, then
    __MXGW_BATCH_EOR__ (errors do NOT exit the loop)
  - empty line or EOF terminates the loop

Per-CLI additions:

  .NET: RunBatchAsync + per-line StringWriter capture, JSON error
    envelope when forceJsonErrors is true. Two new tests in
    MxGatewayClientCliTests covering the success and error paths.

  Go:   runBatch with bufio.Scanner, runs each line through the
    existing runWithIO switch with a buffered stdout writer. One new
    test pinning the EOR sentinel.

  Rust: new `Batch` variant on the clap Command enum, run_batch
    re-parses each line via Cli::try_parse_from. Two new tests in the
    inline mod tests block.

  Python: new `batch` click command in commands.py that uses
    CliRunner to dispatch each line; synthesises {"error",..."type"}
    JSON from click error messages when the captured output isn't
    already JSON-shaped. Three new tests in test_cli.py.

  Java: BatchCommand inner @Command with BufferedReader stdin loop,
    fresh commandLine() per dispatch with captured stdout/stderr
    PrintWriters; non-zero exit codes and uncaught exceptions both
    surface as JSON-error blocks. Two new tests.

Also fixes scripts/run-client-e2e-tests.ps1 line 705: the Python
invocation was still passing the old module name `mxgateway_cli` to
`python -m`; the client SDK rename in 397d3c5 moved it to
`zb_mom_ww_mxgateway_cli`. Without the fix the Python leg fails
with "No module named mxgateway_cli" before reaching open-session.

Verification: full matrix at the redeployed gateway (localhost:5120,
running ZB.MOM.WW.MxGateway.Server.exe / ZB.MOM.WW.MxGateway.Worker.exe)
with -SkipBulk -SkipReadWriteBulk -SkipParity -SkipAuth (those phases
exercise bulk read/write CLI subcommands that also live on the
divergent branch — porting those is a follow-up). All five clients
report `closed=true, addedItems=120, eventCount=5` and overall
`success=true`. Per-language unit tests pass:
  - dotnet: 59/59
  - go:     all packages clean
  - rust:   cargo test --workspace clean
  - python: 42/42
  - java:   gradle build SUCCESSFUL

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/run-client-e2e-tests.ps1

@@ -702,7 +702,7 @@ function Get-ClientCommand {
         }
         "python" {
             $arguments = @(
-                "-m", "mxgateway_cli", $Operation,
+                "-m", "zb_mom_ww_mxgateway_cli", $Operation,
                 "--endpoint", $hostEndpoint,
                 "--api-key-env", $ApiKeyEnvName,
                 "--plaintext",