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/api/src/customers/customers.controller.ts

@@ -16,6 +16,7 @@ import { AbilityGuard } from "../auth/ability.guard";
 import { RequireAbility } from "../auth/require-ability.decorator";
 import { AuditService } from "../common/audit.service";
 import { CustomersService } from "./customers.service";
+import { NumidService } from "./numid.service";
 import { CreateCustomerDto } from "./create-customer.dto";
 import { UpdateCustomerDto } from "./update-customer.dto";
 
@@ -24,6 +25,7 @@ import { UpdateCustomerDto } from "./update-customer.dto";
 export class CustomersController {
   constructor(
     private readonly customers: CustomersService,
+    private readonly numids: NumidService,
     private readonly audit: AuditService,
   ) {}
 
@@ -36,6 +38,13 @@ export class CustomersController {
     return this.customers.stats();
   }
 
+  /** Reusable portal ids, lowest first. Declared above `:id` so the literal
+   *  path is not swallowed by the wildcard route. */
+  @Get("numid/candidates")
+  async numidCandidates() {
+    return { candidates: await this.numids.emptyCandidates() };
+  }
+
   @Get()
   list(
     @Query("query") query?: string,
@@ -95,4 +104,27 @@ export class CustomersController {
     void this.audit.log(this.actingId(req), "customer.restore", { customerId: id });
     return c;
   }
+
+  /**
+   * Give this customer a portal NUMid so they can log in to
+   * my.jorgecuadros.com. Idempotent — a customer who already has one gets it
+   * back rather than a second identity.
+   */
+  @Post(":id/portal-access")
+  @RequireAbility("customer:portal-access")
+  async portalAccess(@Param("id") id: string, @Req() req: Request) {
+    const allocation = await this.numids.allocate(id);
+    if (allocation.origin !== "existing") {
+      // Logged with the origin and the previous holder: a recycled id is the one
+      // case where reading this record later has to answer "whose number was
+      // this before, and was it taken or minted".
+      void this.audit.log(this.actingId(req), "customer.portal-access", {
+        customerId: id,
+        numid: allocation.numid,
+        origin: allocation.origin,
+        previousCustomerId: allocation.previousCustomerId,
+      });
+    }
+    return allocation;
+  }
 }