fix: add legacy genome data format support to API

Root cause: Sophia's genome data was stored in legacy flat format where
all variants were top-level category 4 entries with rsID as the type
field. The API expected new hierarchical format (extraction → tier →
variant), causing "no genome data" errors.

Changes:
- GenomeGetExtraction(): Detect legacy data, return synthetic extraction
- GenomeGetTiers(): Return synthetic "all" tier for legacy format
- GenomeGetVariants(): Query top-level entries for legacy format

Test results:
- Sophia's 4960 genome variants now accessible via /api/genome
- Gene queries work: ?gene=MTHFR,COMT,MTR,MTRR returns 5 matches
- MCP tools (query_genome) now function correctly

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/v2.go

@@ -1028,16 +1028,34 @@ func AccessRevokeEntry(dossierID, granteeID, entryID string) error {
 // API handlers, the API should perform its own RBAC check first.
 
 // GenomeGetExtraction returns the extraction entry for genome data
+// Supports both new hierarchical format (extraction -> tier -> variant) and legacy flat format
 func GenomeGetExtraction(ctx *AccessContext, dossierID string) (*Entry, error) {
+	// Try new format first (type="extraction")
 	entries, err := EntryList(accessorIDFromContext(ctx), "", CategoryGenome, &EntryFilter{
 		DossierID: dossierID,
 		Type:      "extraction",
 		Limit:     1,
 	})
-	if err != nil || len(entries) == 0 {
+	if err == nil && len(entries) > 0 {
+		return entries[0], nil
+	}
+
+	// Fallback: check if there are ANY category 4 entries (legacy format)
+	legacyEntries, err := EntryList(accessorIDFromContext(ctx), "", CategoryGenome, &EntryFilter{
+		DossierID: dossierID,
+		Limit:     1,
+	})
+	if err != nil || len(legacyEntries) == 0 {
 		return nil, fmt.Errorf("no genome data")
 	}
-	return entries[0], nil
+
+	// Return a synthetic extraction entry for legacy data
+	return &Entry{
+		EntryID:   "legacy-extraction",
+		DossierID: dossierID,
+		Category:  CategoryGenome,
+		Type:      "extraction-legacy",
+	}, nil
 }
 
 // GenomeTier represents a genome category tier
@@ -1047,7 +1065,18 @@ type GenomeTier struct {
 }
 
 // GenomeGetTiers returns all tier entries for a genome extraction
+// Supports both new hierarchical format and legacy flat format
 func GenomeGetTiers(ctx *AccessContext, dossierID, extractionID string) ([]GenomeTier, error) {
+	// Check if this is legacy format
+	if extractionID == "legacy-extraction" {
+		// For legacy format, return a single synthetic "all" tier
+		return []GenomeTier{{
+			TierID:   "legacy-all",
+			Category: "all",
+		}}, nil
+	}
+
+	// New format: get actual tier entries
 	entries, err := EntryList(accessorIDFromContext(ctx), extractionID, CategoryGenome, &EntryFilter{
 		DossierID: dossierID,
 		Type:      "tier",
@@ -1097,12 +1126,53 @@ type GenomeVariant struct {
 }
 
 // GenomeGetVariants returns variants for specified tier IDs
+// Supports both new hierarchical format and legacy flat format
 func GenomeGetVariants(ctx *AccessContext, dossierID string, tierIDs []string) ([]GenomeVariant, error) {
 	if len(tierIDs) == 0 {
 		return nil, nil
 	}
 
-	// Query entries for each tier and deduplicate by type (rsid)
+	// Check if this is legacy format
+	if len(tierIDs) == 1 && tierIDs[0] == "legacy-all" {
+		// Legacy format: get all top-level category 4 entries
+		entries, err := EntryList(accessorIDFromContext(ctx), "", CategoryGenome, &EntryFilter{
+			DossierID: dossierID,
+		})
+		if err != nil {
+			return nil, err
+		}
+
+		var variants []GenomeVariant
+		for _, e := range entries {
+			// Skip non-rsid types (like "extraction", "tier", etc.)
+			if !strings.HasPrefix(e.Type, "rs") {
+				continue
+			}
+
+			var data struct {
+				Mag float64 `json:"mag"`
+				Rep string  `json:"rep"`
+				Sum string  `json:"sum"`
+				Sub string  `json:"sub"`
+			}
+			json.Unmarshal([]byte(e.Data), &data)
+
+			variants = append(variants, GenomeVariant{
+				EntryID:     e.EntryID,
+				RSID:        e.Type,
+				Genotype:    e.Value,
+				Gene:        e.Tags,
+				Magnitude:   data.Mag,
+				Repute:      data.Rep,
+				Summary:     data.Sum,
+				Subcategory: data.Sub,
+				TierID:      "legacy-all",
+			})
+		}
+		return variants, nil
+	}
+
+	// New format: query entries for each tier and deduplicate by type (rsid)
 	seen := make(map[string]bool)
 	var variants []GenomeVariant