[WIP] [WIP] Address feedback on semantic identifiers and classic-mode lookup regression

[Copilot]

Thanks for the feedback on #23203. I've created this new PR, which merges into #23203, to address your comment. I will work on the changes and keep this PR's description up to date as I make progress.

Original PR: #23203
Triggering review: #23203 (comment)

@copilot you're right that the classic-mode lookup regresses what the prior cache short-circuited. The structural fix is in the stacked follow-up #23221, which restores the per-render preload: with_preloaded_resources returns before priming the lookup unless semantic mode is active, so work_package_for yields nil in classic mode and the handler renders from fallback_id without any SELECT. The classic-mode spec at work_packages_spec.rb:125 pins this with expect(wp_selects).to be_empty.

[akabiru]

Already done!