Fix docs gulp race condition with dsl target directories

The gulpfile.js glob pattern '../dsl/**/src/main/docs/...' uses **
which recurses into target/ directories created by concurrent builds.
When a test process deletes target/surefire while gulp is scanning,
it causes an ENOENT error that fails the docs build.

Fix by replacing ** with explicit depth patterns:
- dsl/src/main/docs/... for depth-0 (dsl.adoc)
- dsl/{*,*/!(target)}/src/main/docs/... for depth 1-2, excluding
  target directories via extglob

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: gnodet

docs/gulpfile.js

@@ -206,7 +206,8 @@ const sources = {
         '../core/camel-base/src/main/docs/!(*-component|*-language|*-dataformat|*-summary).adoc',
         '../core/camel-main/src/main/docs/!(*-component|*-language|*-dataformat|*-summary).adoc',
         '../components/{*,*/*}/src/main/docs/!(*-component|*-language|*-dataformat|*-summary).adoc',
-        '../dsl/**/src/main/docs/!(*-component|*-language|*-dataformat|*-summary).adoc',
+        '../dsl/src/main/docs/!(*-component|*-language|*-dataformat|*-summary).adoc',
+        '../dsl/{*,*/!(target)}/src/main/docs/!(*-component|*-language|*-dataformat|*-summary).adoc',
       ],
       destination: 'components/modules/others/pages',
       keep: [