[raycicmd] Expand array selectors in group-level depends_on

[andrew-anyscale]

Group-level depends_on entries that reference array steps were not being expanded. A selector like build-step(*) passed through raw to Buildkite, which rejected it because parentheses are not valid in step key references.

Apply the same selector parsing used for step-level depends_on:

• (*) expands to all array variants
• (key=val) filters to matching variants
• ($) is rejected with a clear error (groups have no current
  array element for implicit dimension matching)
• Bare references to array steps expand to all variants

Topic: fix-group-deps-star
Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com
Signed-off-by: andrew andrew@anyscale.com

[andrew-anyscale]

Reviews in this chain:
└#475 [raycicmd] Expand array selectors in group-level depends_on

[andrew-anyscale]

#	head	base	diff	date	summary
0	3cf17626	ec4c235a	diff	Mar 30 11:48 AM	3 files changed, 144 insertions(+), 11 deletions(-)
1	8bc1aebd	ec4c235a	diff	Mar 30 12:58 PM	2 files changed, 56 insertions(+), 74 deletions(-)

[gemini-code-assist]

Code Review

This pull request adds support for array selector syntax, such as '(*)' and '(key=val)', to group-level 'depends_on' entries by introducing a new 'resolveGroupDependsOn' function. The reviewer recommended optimizing the 'result' slice allocation in this new function for better performance and suggested refactoring the newly added tests into a table-driven format to improve maintainability and reduce code duplication.