move to generated mcp for econet

AGENTS.md

@@ -24,8 +24,14 @@ Exporter for Rheem EcoNet / Rheemcloud water heaters, built on the
   **No MQTT**, so `WiFiSignal` and `Running`/`RunningState` stay zero.
 - `pkg/econet/econetgrpc/` — `EconetService` gRPC impl (`ListDevices`,
   `GetDevice`) + `deviceToProto`. Does **not** own a client; it's injected.
-- `pkg/econet/econetmcp/` — MCP server at `/api/mcp`; the `list_water_heaters`
-  tool delegates to the gRPC server.
+- `pkg/econet/econetmcpgen/` — **active** MCP server at `/api/mcp`. Registers
+  the tools generated by protoc-gen-go-mcp (`api/econet/v1alpha1/v1alpha1mcp/`)
+  against our go-sdk `*mcp.Server` via the `runtime/gosdk` adapter, forwarding
+  in-process to the gRPC server. Exposes the same package API as `econetmcp`.
+- `pkg/econet/econetmcp/` — the older hand-written MCP server; a single
+  `list_water_heaters` tool delegating to the gRPC server. Kept in place as a
+  fallback. **Switch between the two** with the aliased `econetmcp` import in
+  `pkg/econet/econet.go` (one line — both packages export identical symbols).
 - `pkg/econet/econetmetrics/` — OTEL observable gauges (read the client
   snapshot at scrape time; no poller of its own).
 
@@ -68,6 +74,8 @@ that's all it takes — no extra wiring.
 ## Workflow
 
 - Regenerate proto: `make proto` (buf; `PROTO_DIRS=proto/econet/v1alpha1/*`).
+  This also runs the `protoc-gen-go-mcp` plugin (see `buf.gen.yaml`), emitting
+  the MCP registrars under `api/econet/v1alpha1/v1alpha1mcp/`.
 - Regenerate config schema after config changes: `make schema`.
 - Build/test: `go build ./... && go test ./...`.
 - `econetclient.Device` is a plain struct, so `deviceToProto` and the datapoint