web: add DZDP concentration view to geolocation explorer

CHANGELOG.md

@@ -0,0 +1,11 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
+
+## [Unreleased]
+
+### Added
+- DZDP concentration view in geolocation explorer with hero stats, anchor point map, country bar chart, ASN concentration list, and CTA banner (#550)
+- View switcher (QA Explorer / DZDP Concentration / DZDP Validators) with URL query param sync (#550)

api/handlers/geo_concentration.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"log/slog"
 	"math"
 	"net/http"
 	"sort"
@@ -150,9 +151,12 @@ func (a *API) FetchGeoConcentrationData(ctx context.Context) (*GeoConcentrationR
 	rows, err := a.DB.Query(ctx, query)
 	metrics.RecordClickHouseQuery(time.Since(start), err)
 	if err != nil {
-		// Return empty response when DZDP tables aren't available or accessible
+		// Return empty response when DZDP tables aren't available or accessible.
+		// Code 60 = UNKNOWN_TABLE, Code 81 = UNKNOWN_DATABASE, Code 497 = NOT_ENOUGH_PRIVILEGES.
 		var chErr *proto.Exception
-		if errors.As(err, &chErr) && (chErr.Code == 60 || chErr.Code == 497) {
+		if errors.As(err, &chErr) && (chErr.Code == 60 || chErr.Code == 81 || chErr.Code == 497) {
+			slog.Warn("geo concentration: DZDP tables not available, returning empty response",
+				"dzdp_db", dzdpDB, "ch_error_code", chErr.Code, "error", err)
 			return &GeoConcentrationResponse{
 				Metros:    []GeoConcentrationMetro{},
 				Countries: []GeoConcentrationCountry{},

api/handlers/geo_validators.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"log/slog"
 	"math"
 	"net/http"
 	"sort"
@@ -181,9 +182,12 @@ func (a *API) FetchGeoValidatorsData(ctx context.Context, metro, dzFilter string
 	rows, err := a.DB.Query(ctx, query)
 	metrics.RecordClickHouseQuery(time.Since(start), err)
 	if err != nil {
-		// Return empty response when DZDP tables aren't available or accessible
+		// Return empty response when DZDP tables aren't available or accessible.
+		// Code 60 = UNKNOWN_TABLE, Code 81 = UNKNOWN_DATABASE, Code 497 = NOT_ENOUGH_PRIVILEGES.
 		var chErr *proto.Exception
-		if errors.As(err, &chErr) && (chErr.Code == 60 || chErr.Code == 497) {
+		if errors.As(err, &chErr) && (chErr.Code == 60 || chErr.Code == 81 || chErr.Code == 497) {
+			slog.Warn("geo validators: DZDP tables not available, returning empty response",
+				"dzdp_db", dzdpDB, "ch_error_code", chErr.Code, "error", err)
 			return &GeoValidatorsResponse{
 				Validators:       []GeoValidatorItem{},
 				TierDistribution: []GeoTierDistribution{},

docs/work-plan-550.md

@@ -0,0 +1,29 @@
+# Work Plan: Issue #550 — Geolocation Explorer DZDP Concentration View
+
+## Requirements
+
+1. **View switcher** in `geoloc-explorer-page.tsx` with tabs: QA Explorer / DZDP Concentration / DZDP Validators
+2. **URL query param sync** — `?view=concentration` etc., default to explorer
+3. **DZDP Concentration view** (`dzdp-concentration-view.tsx`):
+   - Hero stat row (4 metric cards with warning states)
+   - Anchor point map (MapLibre, metro dots with proportional rings, hover tooltips)
+   - Stake by country horizontal bar chart (Recharts, warning badges for >8%)
+   - ASN concentration list (concentrated/normal badges)
+   - "How it works" explainer strip
+   - CTA banner linking to https://doublezero.xyz/geolocation-interest
+4. **DZDP Validators** tab — placeholder "Coming soon"
+
+## Design
+
+- View switcher uses `useSearchParams` for URL state
+- Concentration view uses existing `fetchGeoConcentration` API + `fetchMetros` for coordinates
+- API types added to `web/src/lib/api.ts` (will be superseded when #549 merges)
+- All components follow existing patterns (Tailwind v4, lucide icons, Recharts, MapLibre)
+
+## Status
+
+- [x] View switcher with URL param sync
+- [x] DZDP Concentration view implementation
+- [x] TypeScript types for API response
+- [x] CHANGELOG updated
+- [ ] Reviews and PR