harden history find tokens and shops earch

RETRIEX_SHOP_QUERY_CONTEXT_FALLBACK_HOTFIX_README.md

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+# RetrieX Shop Query Context Fallback Hotfix
+
+Patch-only hotfix for meta shop follow-ups such as `suche im shop`.
+
+## Problem
+
+After several shop meta follow-ups, the previous non-meta product/advisory question could fall outside the small context fallback window. The guard then correctly rejected `shop` as a query, but failed to derive a compact query from the last real topic.
+
+## Fix
+
+- Keep the language-preservation and meta-query guard behavior.
+- Increase the configurable fallback question window.
+- Add a separate configurable extended history budget for meta shop fallbacks.
+- If the normal commerce history does not provide a concrete query, scan a larger recent history window for the last non-meta user question.
+- Still compact the question into product/search tokens before sending it to Shopware.
+
+## Expected example
+
+`mit welchem testomat kann ich freies chlor messen` followed by `suche im shop` should resolve to a compact query such as:
+
+```text
+testomat freies chlor
+```
+
+It must not send:
+
+```text
+shop
+mit welchem testomat kann ich freies chlor messen
+```
+
+## Scope
+
+No retrieval, vector, scoring, prompt-answering, product-family special case, Testomat-specific hardcoding or Shopware API changes.