fix(api-server): simplify and fix hostname inspection for multi-zone …

[lukidzi]

Summary

In multi-zone setups, hostname generators may use origin-based selectors (e.g., kuma.io/origin label). Resources synced across zones can appear with different origins depending on perspective. The global control plane now tests both perspectives to ensure all possible hostnames are discovered.

Changes

• Extracted duplicate hostname generation logic into generateAndRecord helper function
• Simplified origin testing logic from duplicated code blocks to a clean loop-based approach
• Added isGlobal parameter to hostname inspection endpoints
• Global control planes now test both Zone and Global origin perspectives to capture all hostname matches
• Zone control planes only test the actual service origin for efficiency

Testing

• Added dedicated test suite for global mode in endpoints_table_test.go
• Organized test data into zone/ and global/ subdirectories

[github-actions]

Reviewer Checklist

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If something doesn't apply please check the box and add a justification if the reason is non obvious.

• Is the PR title satisfactory? Is this part of a larger feature and should be grouped using > Changelog?
• PR description is clear and complete. It Links to relevant issue as well as docs and UI issues
• This will not break child repos: it doesn't hardcode values (.e.g "kumahq" as an image registry)
• IPv6 is taken into account (.e.g: no string concatenation of host port)
• Tests (Unit test, E2E tests, manual test on universal and k8s)
  • Don't forget ci/ labels to run additional/fewer tests
• Does this contain a change that needs to be notified to users? In this case, UPGRADE.md should be updated.
• Does it need to be backported according to the backporting policy? (this GH action will add "backport" label based on these file globs, if you want to prevent it from adding the "backport" label use no-backport-autolabel label)