Stock Valuation Layer Inventory Filter

This module improves the Inventory Valuation report (the list of stock valuation layers) by making it easier to search and organise the entries.

What changes for users:

• A new Reference column is available on stock valuation layers, so each valuation line can show a reference value.
• On the Inventory Valuation search panel you get a new Inventory filter that shows only valuation lines coming from inventory adjustments.
• A new Date filter lets you narrow the valuation lines by their creation date.
• A new Reference grouping option lets you group valuation lines by reference, so you can see totals per reference.

Where it appears: these options are added to the existing Inventory Valuation search view inherited from the stock_account module, on the stock.valuation.layer model. No new menus or buttons are created.

The module only extends the stock.valuation.layer model with the Reference field and adds search filters and grouping. It does not add automatic checks, computations, emails or scheduled jobs. The Reference field is stored and read-only, so it is filled by the system rather than typed by users.