Add HPOS compatibility in Dokan — WPML integration

[dev-shahed]

Description

We’re seeing a gap in Dokan’s WPML integration when sites use WooCommerce HPOS (High Performance Order Storage). HPOS changes how WooCommerce stores order-related data (moving some data off wp_posts/wp_postmeta into custom tables), and WPML/WooCommerce Multilingual added explicit HPOS support starting with recent releases. Dokan relies on WooCommerce/Dokan order data and store metadata for vendor dashboards, translations, and counts — if HPOS is enabled the existing WPML + Dokan interaction can break translations, vendor views, or order-related UI strings. This discussion documents the issue from a QA perspective so maintainers can triage compatibility work.

Key why-it-matters: sites using HPOS (or planning to migrate to HPOS for scale) expect Dokan + WPML to keep vendor-facing content, translated strings, and order metadata consistent across languages. Broken behavior degrades merchant experience, leads to missing translations in vendor dashboards, and may show incorrect order counts or untranslated strings.

Relevant WPML notes: WooCommerce Multilingual announced HPOS support in 2023 — implementations relying on post/meta storage need verification. 

⸻

Actual Behavior
• On a Dokan site with WPML + WooCommerce Multilingual and HPOS enabled, vendor dashboards (or store pages) may show missing translations, incorrect product/order counts, or untranslated strings that previously worked when orders were stored in wp_posts/wp_postmeta.
• WPML’s string and custom type registration may not pick up Dokan-specific data that now lives in HPOS tables; translation editors show incomplete data.
• Some Dokan screens that query order metadata or postmeta for vendor stats return empty or inconsistent values when HPOS is active.
• Admins report mismatched language versions of vendor-generated content (store notices, shipping / delivery strings) in translated sites.

(These are observed symptom patterns — see Reproduction steps below to validate in a test environment.)

⸻

Expected Behavior
• Dokan should behave identically with HPOS enabled or disabled: vendor dashboards, order counts, and all Dokan-related strings should be available to WPML for translation and rendering in each language.
• Dokan should register and expose any custom data (orders, vendor metadata, strings) regardless of whether that data is stored in postmeta or HPOS custom tables so WPML / WooCommerce Multilingual can translate and sync correctly.
• Translated vendor-facing pages (store pages, product titles/descriptions, vendor notices, and order-related messages) should render the correct language and reflect accurate order/item counts.