Rewrite variety score and suggestions with configurable scoring

- Add VarietyScoreConfig entity, repository, and V020 migration for
  per-household scoring weights and configurable tag types
- Rewrite getVarietyScore: tag-type repeats on consecutive days,
  non-staple ingredient overlaps, cooking log history, plan duplicates
- Rewrite getSuggestions: simulate variety score for each candidate,
  add tag filter (AND, case-insensitive) and configurable topN param
- Update SuggestionResponse to return simulatedScore instead of
  fitReasons/warnings, update VarietyScoreResponse to new shape
- Seed default VarietyScoreConfig on household creation
- Extend test suite across all domains (+270 tests, all passing)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/main/java/com/recipeapp/planning/entity/VarietyScoreConfig.java

@@ -0,0 +1,76 @@
+package com.recipeapp.planning.entity;
+
+import com.recipeapp.household.entity.Household;
+import jakarta.persistence.*;
+
+import java.math.BigDecimal;
+import java.util.Arrays;
+import java.util.List;
+import java.util.UUID;
+
+@Entity
+@Table(name = "variety_score_config")
+public class VarietyScoreConfig {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.UUID)
+    private UUID id;
+
+    @OneToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "household_id", nullable = false, unique = true)
+    private Household household;
+
+    @Column(name = "repeat_tag_types", nullable = false, columnDefinition = "text[]")
+    private String[] repeatTagTypes;
+
+    @Column(name = "w_tag_repeat", nullable = false, precision = 3, scale = 1)
+    private BigDecimal wTagRepeat;
+
+    @Column(name = "w_ingredient_overlap", nullable = false, precision = 3, scale = 1)
+    private BigDecimal wIngredientOverlap;
+
+    @Column(name = "w_recent_repeat", nullable = false, precision = 3, scale = 1)
+    private BigDecimal wRecentRepeat;
+
+    @Column(name = "w_plan_duplicate", nullable = false, precision = 3, scale = 1)
+    private BigDecimal wPlanDuplicate;
+
+    @Column(name = "history_days", nullable = false)
+    private int historyDays;
+
+    protected VarietyScoreConfig() {}
+
+    public VarietyScoreConfig(Household household, String[] repeatTagTypes,
+                               BigDecimal wTagRepeat, BigDecimal wIngredientOverlap,
+                               BigDecimal wRecentRepeat, BigDecimal wPlanDuplicate,
+                               int historyDays) {
+        this.household = household;
+        this.repeatTagTypes = repeatTagTypes;
+        this.wTagRepeat = wTagRepeat;
+        this.wIngredientOverlap = wIngredientOverlap;
+        this.wRecentRepeat = wRecentRepeat;
+        this.wPlanDuplicate = wPlanDuplicate;
+        this.historyDays = historyDays;
+    }
+
+    public static VarietyScoreConfig defaults(Household household) {
+        return new VarietyScoreConfig(
+                household,
+                new String[]{"protein", "cuisine"},
+                new BigDecimal("1.5"),
+                new BigDecimal("0.3"),
+                new BigDecimal("1.0"),
+                new BigDecimal("2.0"),
+                14
+        );
+    }
+
+    public UUID getId() { return id; }
+    public Household getHousehold() { return household; }
+    public List<String> getRepeatTagTypes() { return Arrays.asList(repeatTagTypes); }
+    public BigDecimal getWTagRepeat() { return wTagRepeat; }
+    public BigDecimal getWIngredientOverlap() { return wIngredientOverlap; }
+    public BigDecimal getWRecentRepeat() { return wRecentRepeat; }
+    public BigDecimal getWPlanDuplicate() { return wPlanDuplicate; }
+    public int getHistoryDays() { return historyDays; }
+}