feat: reuse resources and blocks across page loads

[shariquerik]

Summary

Navigating between Studio pages was always a cold load: every resource refetched and the whole block tree was reinstantiated. Three related changes:

• Cache API resource data across page loads. Adds a "Cache data across page loads" checkbox for API Resources, so fetched data is reused instead of refetched. The cache key is derived from resource name, url, method, and resolved params, since createResource returns a cache hit before url/params/transform are applied — a name-only key would serve one page's data to another.
• Don't clear resources while new ones resolve. setPageResources reset resources to {} before awaiting the resource promises, leaving components rendered against an empty map for the duration of the fetch. With caching on, that turned an instant cache hit into a flash of empty state. The map is now built locally and swapped in atomically.
• Keep the block tree mounted on same-page navigation. The route watcher rebuilt rootBlock on every path change, so navigating between routes served by the same page (a list and its detail route, a view switch) destroyed component state. It now tracks the last rendered path: same-page navigation still refreshes resources and the page script, since route params may have changed, but leaves the existing blocks in place.

Test plan

• Add an API Resource to a Studio page, enable "Cache data across page loads", confirm data persists across navigation without refetching
• Confirm resources without caching enabled still fetch fresh data as before
• Confirm checkbox only shows for API Resource type
• Navigate between two routes served by the same page and confirm the blocks stay mounted (component state survives) while route-param-dependent resources re-resolve
• Navigate to a different page and confirm the block tree is rebuilt as before

[greptile-apps]

Confidence Score: 5/5

Safe to merge; all three changes are narrowly scoped and the logic is correct.

The cache key includes url, method, and serialized params so cross-page data bleed is not possible. The atomic resource swap and same-page block reuse are straightforward and well-guarded.

studio/studio/doctype/studio_page_resource/studio_page_resource.json — cache field lacks a depends_on guard.

_{Reviews (5): Last reviewed commit: "fix: keep the block tree mounted on same..." | Re-trigger Greptile}