docs: audit facts, wording, and bilingual consistency

[Cc-Cece]

Summary

• audit all 50 Chinese docs and their 50 English counterparts for structure, links, encoding, wording, and source-verifiable facts
• correct WebShopX algorithm documentation to match current implementation: transactional row locking, step-based pressure decay, linear Dutch pricing, and candle-auction extension timing
• correct WebShopX-Payments runtime/build Java guidance, Hook timing wording, retry guarantees, fee claims, currency examples, and the English issue tracker
• complete the documented product-type list, fix heading/link consistency, and remove four UTF-8 BOM markers

Source checks

Compared against the current local source trees for:

• WebShopX command/permission declarations, product types, dynamic pricing, auction settlement, and payment-provider behavior
• WebShopX-Payments plugin permissions, Gradle target/CI JDK, channel config, and notification retry implementation

Validation

• npm run check:frontmatter
• npm run check:encoding
• npm run typecheck
• npm run build (zh-CN + en; 50 Chinese documents and 100 localized Markdown routes; no broken-anchor warning)
• git diff --check

Review focus

1. Confirm the algorithm behavior descriptions against the current WebShopX implementation.
2. Confirm the Payments Java compatibility wording and operational caveats.
3. Review softened claims around fees, latency, retries, and production readiness.
4. Confirm Chinese/English terminology and the added product-type rows.