A SimpleX Chat bot that answers arithmetic (closes #1)

Remove the template's HTTP service, database and fx wiring. Add exact
arithmetic on go/parser and go/constant, a client that runs simplex-chat
as a child process and drives its WebSocket API, and the bot, which keeps
an auto-accepting address and replies to each message. The image adds the
checksum-pinned simplex-chat v7.0.2 on Ubuntu 22.04.

Model: opus-5-5

Makefile

@@ -31,11 +31,13 @@ check:
 build:
 	go build -o bin/simplexcalc ./cmd/simplexcalc
 
+# run and dev need the simplex-chat command-line client on PATH; the
+# image built by `make docker` carries its own.
 run: build
-	./bin/simplexcalc serve
+	./bin/simplexcalc run
 
 dev:
-	go run ./cmd/simplexcalc serve
+	go run ./cmd/simplexcalc run
 
 deps:
 	go mod download