feat: add environment filtering across all APIs and UI

Backend: Added optional `environment` query parameter to catalog,
search, stats, timeseries, punchcard, top-errors, logs, and agents
endpoints. ClickHouse queries filter by environment when specified
(literal SQL for AggregatingMergeTree, ? binds for raw tables).
StatsStore interface methods all accept environment parameter.

UI: Added EnvironmentSelector component (compact native select).
LayoutShell extracts distinct environments from agent data and
passes selected environment to catalog and agent queries via URL
search param (?env=). TopBar shows current environment label.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/dto/AgentInstanceResponse.java

@@ -14,6 +14,7 @@ public record AgentInstanceResponse(
         @NotNull String instanceId,
         @NotNull String displayName,
         @NotNull String applicationId,
+        String environmentId,
         @NotNull String status,
         @NotNull List<String> routeIds,
         @NotNull Instant registeredAt,
@@ -30,6 +31,7 @@ public record AgentInstanceResponse(
         long uptime = Duration.between(info.registeredAt(), Instant.now()).toSeconds();
         return new AgentInstanceResponse(
                 info.instanceId(), info.displayName(), info.applicationId(),
+                info.environmentId(),
                 info.state().name(), info.routeIds(),
                 info.registeredAt(), info.lastHeartbeat(),
                 info.version(), info.capabilities(),
@@ -41,7 +43,8 @@ public record AgentInstanceResponse(
 
     public AgentInstanceResponse withMetrics(double tps, double errorRate, int activeRoutes) {
         return new AgentInstanceResponse(
-                instanceId, displayName, applicationId, status, routeIds, registeredAt, lastHeartbeat,
+                instanceId, displayName, applicationId, environmentId,
+                status, routeIds, registeredAt, lastHeartbeat,
                 version, capabilities,
                 tps, errorRate, activeRoutes, totalRoutes, uptimeSeconds
         );