hotfix-add subgroup customer

docs/implementation/hotfix-1-customer-sub-group.md

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+# Hotfix 1: Customer Sub Group
+
+## 1. Files Added
+
+- `drizzle/0011_brief_hobgoblin.sql`
+- `docs/implementation/hotfix-1-customer-sub-group.md`
+
+## 2. Files Modified
+
+- `src/db/schema.ts`
+- `src/db/seeds/foundation.seed.ts`
+- `src/features/crm/customers/api/types.ts`
+- `src/features/crm/customers/schemas/customer.schema.ts`
+- `src/features/crm/customers/server/service.ts`
+- `src/app/api/crm/customers/route.ts`
+- `src/app/api/crm/customers/[id]/route.ts`
+- `src/components/forms/fields/select-field.tsx`
+- `src/features/crm/customers/components/customer-form-sheet.tsx`
+- `src/features/crm/customers/components/customer-columns.tsx`
+- `src/features/crm/customers/components/customer-detail.tsx`
+
+## 3. Schema Field Used/Added
+
+- Added optional field `customerSubGroup` to `crm_customers`
+- Field is stored with the same option-id pattern already used by `customerGroup`
+
+## 4. Master Options Seeded
+
+- `crm_customer_group`
+  - `industrial`
+  - `construction`
+  - `government`
+  - `dealer`
+  - `other`
+- `crm_customer_sub_group`
+  - `factory`
+  - `warehouse`
+  - `logistics`
+  - `contractor`
+  - `consultant`
+  - `state_enterprise`
+  - `government_agency`
+  - `reseller`
+  - `other`
+
+Child options resolve and store `parentId` from the seeded `crm_customer_group` rows during idempotent seed execution.
+
+## 5. Form Behavior Added
+
+- Add/Edit Customer now includes `Customer Sub Group`
+- Sub group is disabled until a customer group is selected
+- Edit mode loads the saved group and sub group
+- Submit payload now persists `customerSubGroup`
+
+## 6. Parent/Child Filtering Behavior
+
+- Customer sub group options are filtered by `parentId === selectedCustomerGroup`
+- Changing group clears the sub group when the selected child no longer belongs to the new parent
+- Placeholder shows `Select customer group first` until a parent group is chosen
+
+## 7. Validation Added
+
+- API schemas now accept `customerSubGroup`
+- Server validation checks that:
+  - the selected sub group exists in `crm_customer_sub_group`
+  - a sub group cannot be submitted without a group
+  - the selected sub group belongs to the selected group parent
+- Invalid parent/child combinations return a user-safe `400` error
+
+## 8. Verification Result
+
+- `npx tsc --noEmit` passed
+- CRUD wiring, list/detail output, and form filtering compile successfully
+
+## 9. Remaining Risks
+
+- Database migration `drizzle/0011_brief_hobgoblin.sql` still needs to be applied in the target environment
+- Seed changes were updated in code, but I did not run a live seed against the database in this session
+- Existing customer rows will keep `customerSubGroup = null` until edited or backfilled