Prevent docs gulp build from scanning target directories

[gnodet]

Summary

• Exclude **/target/** from gulp.src() glob scanning in createSymlinks and createExampleSymlinks functions
• The others.asciidoc source pattern uses ../dsl/**/src/main/docs/*.adoc which causes recursive scanning of all directories under dsl/, including target/ directories

Rationale

This is a preventive change, not a fix for a specific observed failure. The ** glob pattern in the others source configuration causes the glob library to recursively scan all directories under ../dsl/, including Maven target/ directories. These directories:

1. Never contain documentation source files, so scanning them is wasted work
2. Can contain ephemeral temp directories (e.g. templates-tmp*) created by Maven plugins during parallel builds, which could cause ENOENT race conditions if a directory appears in a listing but is deleted before scandir reads it

Excluding **/target/** is a safe, no-functional-change improvement that avoids unnecessary I/O and eliminates a potential source of flakiness during parallel CI builds.

[github-actions]

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