echarts to display the datafusion SQL

graphs/README.md

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+# Analytics graphs
+
+A small Rust web server that forwards SQL queries to `AnalyticsService.ExecuteAnalyticsQuery`
+and displays the streamed result with ECharts.
+
+## Run
+
+Start the main komp_ac gRPC server, then run:
+
+```sh
+cargo run
+```
+
+Open <http://127.0.0.1:3000>. The default gRPC endpoint is
+`http://[::1]:50051`. Both addresses can be changed:
+
+```sh
+ANALYTICS_GRPC_ENDPOINT=http://127.0.0.1:50051 \
+LISTEN_ADDRESS=127.0.0.1:8080 \
+cargo run
+```
+
+The first SQL result column is used for category labels. Bar and line charts use
+all remaining columns as numeric series, pie uses the second column, and scatter
+uses the first two columns. Table view displays every returned value.
+
+ECharts is loaded from jsDelivr, so the browser needs network access when opening
+the page.