Add a Crucible API endpoint

Service layer

Add the method in data/api/CrucibleApiService.kt and wrap it with safeCall so non-2xx responses become ApiResult.Error values. The shared client uses expectSuccess = true; do not bypass that behavior.

suspend fun getWidget(widgetId: String): ApiResult<Widget> = safeCall {
    client.get("$baseUrl/widgets/$widgetId").body()
}

Send Authorization: Bearer {apiKey} on authenticated requests. Handle both ApiResult.Success and ApiResult.Error at call sites.

Choose pagination from the endpoint response:

Response	Helper
Offset and limit list	fetchAllPages
Sample or dataset keyset cursor list	fetchAllPagesCursor
Flat search result	No pagination helper

Use explicit @SerialName values for wire fields that must remain stable, including single-word names whose Kotlin property might later be renamed.

Scientific metadata

Sample and dataset create/update DTOs do not accept scientific_metadata; the server silently drops it. Create and edit flows therefore make a structural request and a separate metadata request.

• Metadata POST and PATCH return ApiResult<JsonObject>, not ApiResult<Unit>.
• On create, use a plain metadata POST.
• On edit, use diffMetadataWrite from ui/common/MetadataEditor.kt.
• If no key was deleted, PATCH only the changed top-level keys.
• If a key was deleted, POST ?overwrite=true with the complete object because PATCH cannot express deletion.

Repository and cache

Use CrucibleRepository for data that should be cached or observed by multiple consumers. Back it with ObservableCache, using Unit with maxSize = 1 for a whole collection or an entity ID for per-entity data. Let ObservableCache own TTL and LRU behavior.

Expose observation when screens must react to cache updates. Do not copy an observed repository object into long-lived Compose state.

Skip the repository for a one-shot mutation with nothing to cache. Existing join-request mutations intentionally call apiClient.service from their ViewModels; pending join-request counts remain in the repository because several screens consume them.

Documentation and tests

• Update the endpoint and caching sections of dev/architecture.md.
• Add an Unreleased changelog entry only for a user-visible change.
• Add a common test for new deterministic branching, parsing, sorting, or cache logic. A direct Ktor wrapper without app logic does not require a unit test.

Verify

./scripts/verify-change.sh