aisman

Session 154, Step 2: Fix ReferenceError: suffix is not defined in renderS4DynamicArea
- AIM-2872 Fix ReferenceError: suffix is not defined in renderS4DynamicArea
- AIM-2856 Update 'Add purchase' dialog with purchase type dropdown, pre-population, and new styling
- AIM-2857 Filter 'Manage credit providers' dialog to show only purchases with remaining credit > 0
- AIM-2858 Update Wf S4 dropdown to show provider name with dynamic per-unit rate

Outcome:
**AIM-2856** — Rewrote `_showAddPurchaseDialog` with purchase type dropdown from `p.purchaseTypes`, auto-fill credits/price on type change, sends `purchaseTypeId` to server. Added `_showAddPurchaseTypeDialog` for inline type creation.

**AIM-2857** — Added `remaining > 0` filter in `_renderProviderList`.

**AIM-2858** — Added `_getFifoPurchase`/`_getProviderRate` helpers. Rewrote `_buildCreditProviderMenuItems` for single-line-per-provider with FIFO rate.

**Runtime fix** — Added `var` to `suffix` declaration.