fix(web): merge defaults in parseSettings/parseSchema on successful parse (IDEA-1487)

parseSettings and parseSchema only merged defaults in the catch branch.
Post-PR #562 migration backfilled NULL collections.settings to '{}', so
JSON.parse succeeds and returns a bare object — downstream consumers
read settings.layout as undefined (rendering 'layout-undefined') and
schema.fields.find as a TypeError on any collection with bare '{}'.

Merge SETTINGS_DEFAULTS / SCHEMA_DEFAULTS into the parsed object in both
branches. Explicit user-supplied fields still override defaults.

Note: QuickActionsMenu spreads parseSettings() back to the wire on edit,
so first quick-action save on a previously-bare collection now persists
{layout:'balanced', default_view:'list'} alongside quick_actions. Left
as-is — defaults migrating to wire is harmless and matches what the UI
was already rendering. Reviewer flag, not a regression.

web/src/lib/types/index.ts

@@ -1072,19 +1072,23 @@ export function parseFields(item: Item): Record<string, any> {
 	}
 }
 
+const SCHEMA_DEFAULTS: CollectionSchema = { fields: [] };
+
 export function parseSchema(collection: Collection): CollectionSchema {
 	try {
-		return JSON.parse(collection.schema);
+		return { ...SCHEMA_DEFAULTS, ...JSON.parse(collection.schema) };
 	} catch {
-		return { fields: [] };
+		return { ...SCHEMA_DEFAULTS };
 	}
 }
 
+const SETTINGS_DEFAULTS: CollectionSettings = { layout: 'balanced', default_view: 'list' };
+
 export function parseSettings(collection: Collection): CollectionSettings {
 	try {
-		return JSON.parse(collection.settings);
+		return { ...SETTINGS_DEFAULTS, ...JSON.parse(collection.settings) };
 	} catch {
-		return { layout: 'balanced', default_view: 'list' };
+		return { ...SETTINGS_DEFAULTS };
 	}
 }