Batch Analyse requests and survive opaque provider schema budgets

Analyse now classifies up to ten same-kind transactions per provider
request: the registry and history travel once per batch, so a
thousand-row backfill costs about a hundred paced requests instead of a
thousand. The answer schema appears once — an array item carrying an
enum-bound ref — because providers meter strict schemas by token cost:
duplicating registry enums per row, or bounding arrays with
minItems/maxItems that Gemini expands per element, rejects real
registries with a bare HTTP 400. Row count, duplicate refs, duplicate
tags and taxonomy bounds are all enforced server-side instead, and a
request still rejected outright halves until accepted, remembering the
working size for the run. Batch requests scale the HTTP budget by row
count, chunk failures cannot abort a run whose later rows succeeded,
and rows resolved against one snapshot share one minted merchant.

Measured on a real 165-row month over a zero-data-retention route:
165 analysed, 152 proposals, 0 errors, 17 requests, under 8 minutes.

Fresh installs default to google/gemini-3.8-flash, the model that
demonstrably honors strict structured outputs over a ZDR route. Preview
changes now carry counterparty, amount and currency, and the review
list shows the amount with a counterparty fallback for banks that leave
descriptions empty.

internal/app/app_test.go

@@ -270,6 +270,9 @@ func mockClassifier(t *testing.T, a *App, inspect ...func(*http.Request)) {
 			return
 		}
 		var prompt struct {
+			Transactions []struct {
+				Ref string `json:"ref"`
+			} `json:"transactions"`
 			Categories []struct{ ID, Path string } `json:"categories"`
 		}
 		if len(req.Messages) != 2 || json.Unmarshal([]byte(req.Messages[1].Content), &prompt) != nil {
@@ -282,7 +285,21 @@ func mockClassifier(t *testing.T, a *App, inspect ...func(*http.Request)) {
 				category = c.ID
 			}
 		}
-		content, _ := json.Marshal(map[string]any{"merchant_id": nil, "new_merchant": "REWE", "category_id": category, "tag_ids": []string{}, "confidence": "high"})
+		answer := map[string]any{"merchant_id": nil, "new_merchant": "REWE", "category_id": category, "tag_ids": []string{}, "confidence": "high"}
+		var content []byte
+		if len(prompt.Transactions) > 0 {
+			items := make([]map[string]any, 0, len(prompt.Transactions))
+			for _, row := range prompt.Transactions {
+				item := map[string]any{"ref": row.Ref}
+				for k, v := range answer {
+					item[k] = v
+				}
+				items = append(items, item)
+			}
+			content, _ = json.Marshal(map[string]any{"transactions": items})
+		} else {
+			content, _ = json.Marshal(answer)
+		}
 		json.NewEncoder(w).Encode(map[string]any{"choices": []any{map[string]any{"finish_reason": "stop", "message": map[string]any{"content": string(content)}}}})
 	}))
 	t.Cleanup(mock.Close)