Fix: Hash Stats 'By Repeaters' includes non-repeater nodes (#654)

## Summary

The "By Repeaters" section on the Hash Stats analytics page was counting
**all** node types (companions, room servers, sensors, etc.) instead of
only repeaters. This made the "By Repeaters" distribution identical to
"Multi-Byte Hash Adopters", defeating the purpose of the breakdown.

Fixes #652

## Root Cause

`computeAnalyticsHashSizes()` in `cmd/server/store.go` built its
`byNode` map from advert packet data without cross-referencing node
roles from the node store. Both `distributionByRepeaters` and
`multiByteNodes` consumed this unfiltered map.

## Changes

### `cmd/server/store.go`
- Build a `nodeRoleByPK` lookup map from `getCachedNodesAndPM()` at the
start of the function
- Store `role` in each `byNode` entry when processing advert packets
- **`distributionByRepeaters`**: filter to only count nodes whose role
contains "repeater"
- **`multiByteNodes`**: include `role` field in output so the frontend
can filter/group by node type

### `cmd/server/coverage_test.go`
- Add `TestHashSizesDistributionByRepeatersFiltersRole`: verifies that
companion nodes are excluded from `distributionByRepeaters` but included
in `multiByteNodes` with correct role

### `cmd/server/routes_test.go`
- Fix `TestHashAnalyticsZeroHopAdvert`: invalidate node cache after DB
insert so role lookup works
- Fix `TestAnalyticsHashSizeSameNameDifferentPubkey`: insert node
records as repeaters + invalidate cache

## Testing

All `cmd/server` tests pass (68 insertions, 3 deletions across 3 files).

Co-authored-by: you <you@example.com>

cmd/server/coverage_test.go

@@ -2198,6 +2198,53 @@ func TestStoreGetAnalyticsHashSizes(t *testing.T) {
 	})
 }
 
+func TestHashSizesDistributionByRepeatersFiltersRole(t *testing.T) {
+	db := setupRichTestDB(t)
+	defer db.Close()
+	store := NewPacketStore(db, nil)
+	store.Load()
+
+	result := store.GetAnalyticsHashSizes("")
+
+	// distributionByRepeaters should only count repeater nodes.
+	// Rich test DB: aabbccdd11223344 = repeater (hash size 2), eeff00112233aabb = companion (hash size 3).
+	dbr, ok := result["distributionByRepeaters"].(map[string]int)
+	if !ok {
+		t.Fatal("expected distributionByRepeaters map")
+	}
+	// Only the repeater node should be counted.
+	if dbr["3"] != 0 {
+		t.Errorf("distributionByRepeaters[3] = %d, want 0 (companion should be excluded)", dbr["3"])
+	}
+	if dbr["2"] != 1 {
+		t.Errorf("distributionByRepeaters[2] = %d, want 1 (repeater)", dbr["2"])
+	}
+
+	// multiByteNodes should include role field for frontend filtering.
+	mbn, ok := result["multiByteNodes"].([]map[string]interface{})
+	if !ok {
+		t.Fatal("expected multiByteNodes slice")
+	}
+	for _, node := range mbn {
+		if _, hasRole := node["role"]; !hasRole {
+			t.Errorf("multiByteNodes entry missing 'role' field: %v", node)
+		}
+	}
+	// Verify companion is included in multiByteNodes (it's multi-byte) with correct role.
+	foundCompanion := false
+	for _, node := range mbn {
+		if node["pubkey"] == "eeff00112233aabb" {
+			foundCompanion = true
+			if node["role"] != "companion" {
+				t.Errorf("companion node role = %v, want 'companion'", node["role"])
+			}
+		}
+	}
+	if !foundCompanion {
+		t.Error("expected companion node in multiByteNodes (multi-byte adopters should include all roles)")
+	}
+}
+
 func TestStoreGetAnalyticsSubpaths(t *testing.T) {
 	db := setupRichTestDB(t)
 	defer db.Close()

cmd/server/routes_test.go

@@ -2451,6 +2451,7 @@ func TestHashAnalyticsZeroHopAdvert(t *testing.T) {
 
 	pk := "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee"
 	db.conn.Exec("INSERT OR IGNORE INTO nodes (public_key, name, role) VALUES (?, 'ZeroHop', 'repeater')", pk)
+	store.InvalidateNodeCache()
 
 	decoded := `{"name":"ZeroHop","pubKey":"` + pk + `"}`
 	// header 0x05 → routeType=1 (FLOOD), pathByte=0x00 → hashSize=1
@@ -2504,6 +2505,11 @@ func TestAnalyticsHashSizeSameNameDifferentPubkey(t *testing.T) {
 	pk1 := "aaaa111122223333444455556666777788889999aaaabbbbccccddddeeee1111"
 	pk2 := "aaaa111122223333444455556666777788889999aaaabbbbccccddddeeee2222"
 
+	// Insert both nodes as repeaters so they appear in distributionByRepeaters.
+	db.conn.Exec("INSERT OR IGNORE INTO nodes (public_key, name, role) VALUES (?, 'SameName', 'repeater')", pk1)
+	db.conn.Exec("INSERT OR IGNORE INTO nodes (public_key, name, role) VALUES (?, 'SameName', 'repeater')", pk2)
+	store.InvalidateNodeCache()
+
 	decoded1 := `{"name":"SameName","pubKey":"` + pk1 + `"}`
 	decoded2 := `{"name":"SameName","pubKey":"` + pk2 + `"}`
 

cmd/server/store.go

@@ -4731,7 +4731,13 @@ func (s *PacketStore) computeAnalyticsHashSizes(region string) map[string]interf
 		regionObs = s.resolveRegionObservers(region)
 	}
 
-	_, pm := s.getCachedNodesAndPM()
+	allNodes, pm := s.getCachedNodesAndPM()
+
+	// Build pubkey→role map for filtering by node type.
+	nodeRoleByPK := make(map[string]string, len(allNodes))
+	for _, n := range allNodes {
+		nodeRoleByPK[n.PublicKey] = n.Role
+	}
 
 	distribution := map[string]int{"1": 0, "2": 0, "3": 0}
 	byHour := map[string]map[string]int{}
@@ -4808,9 +4814,11 @@ func (s *PacketStore) computeAnalyticsHashSizes(region string) map[string]interf
 						}
 					}
 					if byNode[pk] == nil {
+						role := nodeRoleByPK[pk] // empty if unknown
 						byNode[pk] = map[string]interface{}{
 							"hashSize": hashSize, "packets": 0,
 							"lastSeen": tx.FirstSeen, "name": name,
+							"role": role,
 						}
 					}
 					byNode[pk]["packets"] = byNode[pk]["packets"].(int) + 1
@@ -4902,7 +4910,7 @@ func (s *PacketStore) computeAnalyticsHashSizes(region string) map[string]interf
 			multiByteNodes = append(multiByteNodes, map[string]interface{}{
 				"name": data["name"], "hashSize": data["hashSize"],
 				"packets": data["packets"], "lastSeen": data["lastSeen"],
-				"pubkey": pk,
+				"pubkey": pk, "role": data["role"],
 			})
 		}
 	}
@@ -4910,9 +4918,13 @@ func (s *PacketStore) computeAnalyticsHashSizes(region string) map[string]interf
 		return multiByteNodes[i]["packets"].(int) > multiByteNodes[j]["packets"].(int)
 	})
 
-	// Distribution by repeaters: count unique nodes per hash size
+	// Distribution by repeaters: count unique REPEATER nodes per hash size
 	distributionByRepeaters := map[string]int{"1": 0, "2": 0, "3": 0}
 	for _, data := range byNode {
+		role, _ := data["role"].(string)
+		if !strings.Contains(strings.ToLower(role), "repeater") {
+			continue
+		}
 		hs := data["hashSize"].(int)
 		key := strconv.Itoa(hs)
 		distributionByRepeaters[key]++