Shorten cache lifetime for location pages to 1 hr

[matt-bernhardt]

** Why are these changes being introduced:

In practice, having location pages last for one week in the cache means that users very rarely see more than one featured expert. We would like users to, as they reload a location page (or visit it more than once) to have a greater probability of seeing different experts.

** Relevant ticket(s):

• https://mitlibraries.atlassian.net/browse/pw-188

** How does this address that need:

This adds a branch to the caching logic in the parent theme, resulting in location pages (those using the location or location-2021 templates) to only be cached for one hour - instead of one week.

This change only applies to anonymous users, and authenticated users should already trigger a from-scratch page rendering each time they hit refresh.

** Document any side effects to this change:

Our cache control logic gets yet more complicated, and this is the first time we're checking page templates in the process (previously we have only used is_page() and the $site variable). However, the is_page_template() function is a stable function provided by WordPress so we don't need to rely on any additional trickery.

Additionally, shortening the cache lifetime in this way is not a guarantee that users will see more experts - the logic that selects an expert is liable to repeatedly land on the same expert, and this outcome gets more likely when there are fewer available experts to choose from. When it isn't clear how often users are loading a location page multiple times, I can't say that this will be hugely impactful.

Developer

Stylesheets

• Any theme or plugin whose stylesheets have changed has had its version
  string incremented.
• No stylesheets are changed

Secrets

• All new secrets have been added to Pantheon tiers
• Relevant secrets have been updated in Github Actions
• All new secrets documented in README
• No secrets are impacted

Documentation

• Project documentation has been updated
• No documentation changes are needed

Accessibility

• ANDI or Wave has been run in accordance to
  our guide and
  all issues introduced by these changes have been resolved or opened as new
  issues (link to those issues in the Pull Request details above)
• No a11y changes are implicated

Stakeholder approval

• Stakeholder approval has been confirmed
• Stakeholder approval is not needed

Dependencies

NO dependencies are updated

Code Reviewer

• The commit message is clear and follows our guidelines
  (not just this pull request message)
• The changes have been verified
• The documentation has been updated or is unnecessary
• New dependencies are appropriate or there were no changes

[Copilot]

Pull request overview

This PR updates Pantheon cache max-age overrides in the parent theme so that location pages rotate featured experts more frequently by reducing their cache lifetime from one week to one hour.

Changes:

• Added a cache-lifetime override branch to detect location page templates.
• Set max-age for location template pages to 1 * HOUR_IN_SECONDS (matching other short-lived pages).

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[matt-bernhardt]

I'm not sure I agree with extraction in this case. Line 282 isn't a clean repetition of this condition, because that check includes the study spaces page:

	if ( is_page_template( 'templates/page-location-2021.php' ) || is_page_template( 'templates/page-location.php' ) || is_page_template( 'templates/page-study-spaces.php' ) ) {
		wp_enqueue_script( 'parent-hours' );
	}

Line 560 is a better match, but on the whole that's now a false promise of abstraction because we'd still need to be aware that there's this one helper method that we need to maintain while there are a lot of other bespoke checks around the source code.

[djanelle-mit]

This works as expected on the multidev, I'm seeing experts rotate after an hour.

The logic check seems really reasonable.

This looks good to me!