feat(properties): warn when parenting exceeds depth cap of 5

Phase 5 polish. Soft cap — properties still save, but a console.warn
fires so journalctl picks up a clear signal when a tree grows
pathologically deep. Triggered on create + on parent reassignment
via updateProperty. Justification for the warning: getDescendantIds
runs an unbounded recursive CTE, and deep hierarchies are also
painful to navigate in the existing list view.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/server/services/properties.ts

@@ -17,6 +17,28 @@ export interface PropertyCreateInput {
 	notes?: string | null;
 }
 
+// Soft cap. Properties past this depth still save, but get logged so a sudden
+// spike in journal entries draws attention to a tree growing pathologically.
+// Exists because getDescendantIds is an unbounded recursive CTE and deep
+// hierarchies are also painful to navigate in the UI.
+const MAX_RECOMMENDED_DEPTH = 5;
+
+async function warnIfDeep(
+	companyId: string,
+	propertyId: string,
+	candidateParentId: string
+): Promise<void> {
+	const parentAncestors = await getAncestorIds(companyId, candidateParentId);
+	const newChildDepth = parentAncestors.length + 1;
+	if (newChildDepth > MAX_RECOMMENDED_DEPTH) {
+		console.warn(
+			`[properties] depth cap exceeded: parenting ${propertyId} under ${candidateParentId} ` +
+				`places it at depth ${newChildDepth} (recommended max: ${MAX_RECOMMENDED_DEPTH}). ` +
+				`Allowed but flagged.`
+		);
+	}
+}
+
 async function assertParentInCompany(companyId: string, parentId: string): Promise<void> {
 	const [row] = await db
 		.select({ id: properties.id })
@@ -35,6 +57,7 @@ async function assertParentInCompany(companyId: string, parentId: string): Promi
 export async function createProperty(input: PropertyCreateInput): Promise<{ id: string }> {
 	if (input.parentId) {
 		await assertParentInCompany(input.companyId, input.parentId);
+		await warnIfDeep(input.companyId, '<new>', input.parentId);
 	}
 	const values: NewProperty = {
 		companyId: input.companyId,
@@ -86,6 +109,7 @@ export async function updateProperty(
 		if (patch.parentId === id) throw new Error('a property cannot be its own parent');
 		await assertParentInCompany(companyId, patch.parentId);
 		await assertNoCycle(companyId, id, patch.parentId);
+		await warnIfDeep(companyId, id, patch.parentId);
 	}
 	await db
 		.update(properties)