feat(customers): allocate portal NUMids, with an audit for reusable ones

Customers created in the staff UI had no NUMid and so could not log in to
my.jorgecuadros.com at all: the id is a CustomerLegacyRef row, not a column,
and create() deliberately writes none.

Allocation is a staff action (POST /customers/:id/portal-access, MANAGER)
rather than part of create, because insurance is expected to move to the
platform before utilities and an insurance-only customer has no reason to
spend a utilities id.

The audit that decides which ids are reusable took three passes. "Owns no
rows" matches nobody -- migration gave all 1,171 NUMids a property and a
transaction. "No transaction in N years" also matches nobody -- every customer
carries a synthetic Jan-1 opening-balance row, so everyone looks active this
year. Subtracting that row is what makes dormancy measurable, and it leaves 4
never-used ids and 10 dormant ones on dev. Two further traps are encoded in the
queries: insurance/DATGRAL is a separate id space that reuses the sourceTable
name and runs past 4,000, and ACCOUNT CANCELED is a transaction line type, not
an account state -- all 8 customers carrying it have current-year activity.

Recycling ships switched off (numid.recycleEmpty, default false). Every
reusable id still exists in Access DATGRAL, and a --sync run reassigns refs
with ON DUPLICATE KEY UPDATE customerId, so an id recycled before the utilities
cutover is silently handed back to its Access owner.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/web/src/lib/api.ts

@@ -232,6 +232,20 @@ export function restoreCustomer(id: string): Promise<CustomerDetail> {
   return apiFetch<CustomerDetail>(`/customers/${id}/restore`, { method: "POST" });
 }
 
+export interface NumidAllocation {
+  numid: string;
+  /** "existing" when the customer already had one — the call is idempotent. */
+  origin: "existing" | "new" | "recycled";
+  previousCustomerId?: string;
+}
+
+/** Give a customer the portal NUMid they log in to my.jorgecuadros.com with. */
+export function grantPortalAccess(id: string): Promise<NumidAllocation> {
+  return apiFetch<NumidAllocation>(`/customers/${id}/portal-access`, {
+    method: "POST",
+  });
+}
+
 /* ------------------------------------------------------ Policies module */
 
 /** Renewal horizon in days, shared by the list, stats and detail calls so the