Opening the Inventory Valuation report iterated every storable product to compute total_value, which on large catalogs used several GB of RAM and timed out workers.

The report now searches only products that have stock (under the same valuation context that total_value uses) or that are lot-valuated, and feeds that smaller set into stock_value and stock_accounting_value. For historical (at_date) reports the search runs with to_date in context so qty_available is scoped to that date. _get_accounts_by_product() also switches to search_fetch so only categ_id is loaded upfront.

Benchmarks were measured on a customer database restore with ~360k storable products. After filtering, ~2.5k products feed into the valuation today and ~2.2k for a historical date.

Benchmark opening Inventory Valuation report (Accounting)
| Date       | Before | After  | Speed up |
|------------|--------|--------|----------|
| Today      | ~88s   | ~2s    | 41x      |
| Historical | ~245s  | ~173s  | 1.4x     |

The historical improvement is more modest because stock_value still has to compute total_value at the historical date for the remaining products, which traces SVL/stock.move history; the filter eliminates the dominant per-product overhead today but only the tail in the historical case.

Description of the issue/feature this PR addresses:

Current behavior before PR:

Desired behavior after PR is merged:




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