fix(raw apps): show the schemas the picked role can reach

frontend/src/lib/components/raw_apps/RawAppTemplatePicker.svelte

@@ -21,9 +21,9 @@
 	import type { Runnable } from './rawAppPolicy'
 	import { type DataTableRef, type RawAppData, formatDataTableRef } from './dataTableRefUtils'
 	import {
+		createDatatableAccessResource,
 		createDatatablesResource,
 		createRolesResource,
-		createSchemasResource,
 		rolesWorthPicking,
 		toDatatableItems,
 		toSchemaItems
@@ -70,8 +70,10 @@
 	let opWs = $derived(getOpWs?.() ?? $workspaceStore)
 
 	const datatables = createDatatablesResource(() => opWs)
-	const schemas = createSchemasResource(
+	// What the picked role can reach, which is not what the data table holds.
+	const access = createDatatableAccessResource(
 		() => selectedDatatable,
+		() => (showRolePicker ? selectedRole : undefined),
 		() => opWs
 	)
 	const roles = createRolesResource(
@@ -95,7 +97,14 @@
 	})
 
 	const availableDatatables = $derived(datatables.current)
-	const availableSchemas = $derived(schemas.current)
+	const availableSchemas = $derived(access.current.schemas)
+	const canCreateSchema = $derived(access.current.canCreateSchema)
+
+	// A role that cannot create schemas has nothing to name, so the mode goes
+	// back to the one every role has.
+	$effect(() => {
+		if (schemaMode === 'new' && !canCreateSchema) schemaMode = 'none'
+	})
 
 	let hasAutoSelected = false
 	$effect(() => {
@@ -316,7 +325,17 @@
 												<ToggleButtonGroup bind:selected={schemaMode} noWFull>
 													{#snippet children({ item })}
 														<ToggleButton value="none" label="None" icon={Ban} {item} size="sm" />
-														<ToggleButton value="new" label="New" icon={Plus} {item} size="sm" />
+														<ToggleButton
+															value="new"
+															label="New"
+															icon={Plus}
+															disabled={!canCreateSchema}
+															tooltip={canCreateSchema
+																? undefined
+																: `${selectedRole ?? 'This role'} cannot create schemas in ${selectedDatatable}`}
+															{item}
+															size="sm"
+														/>
 														<ToggleButton
 															value="existing"
 															label="Existing"

frontend/src/lib/components/raw_apps/datatableUtils.svelte.ts

@@ -87,6 +87,46 @@ export function createRolesResource(
 	)
 }
 
+/**
+ * Creates a resource that loads, for one data table read as one role, the
+ * schemas that role can reach and whether it may create more.
+ *
+ * Both answers are the connected role's, and one call carries them: asking the
+ * schema list of a role that cannot see a schema is the same question as asking
+ * what it may create in.
+ */
+export function createDatatableAccessResource(
+	getDatatable: () => string | undefined,
+	getRole: () => string | undefined,
+	getWorkspace: () => string | undefined = () => get(workspaceStore)
+) {
+	return resource(
+		() => [getDatatable() ?? '', getRole() ?? '', getWorkspace() ?? ''] as const,
+		async ([datatable, role, workspace]): Promise<{
+			schemas: string[]
+			canCreateSchema: boolean
+		}> => {
+			if (!datatable || !workspace) return { schemas: [], canCreateSchema: false }
+			try {
+				const tables = await WorkspaceService.listDataTableTables({
+					workspace,
+					roleFor: datatable,
+					role: role || undefined
+				})
+				const entry = tables.find((t) => t.datatable_name === datatable)
+				return {
+					schemas: Object.keys(entry?.schemas ?? {}).sort(),
+					canCreateSchema: !!entry?.can_create_schema
+				}
+			} catch (e) {
+				console.error('Failed to load datatable access:', e)
+				return { schemas: [], canCreateSchema: false }
+			}
+		},
+		{ initialValue: { schemas: [], canCreateSchema: false } }
+	)
+}
+
 /**
  * Whether naming a role says anything here: a data table without permissions has
  * none to pick, and one whose single role is the implicit `admin` has no choice