docs: update README, AGENTS.md, Makefile, and architecture docs

README.md

@@ -35,23 +35,24 @@ go install github.com/rcarmo/webterm/cmd/webterm@latest
 ```bash
 git clone https://github.com/rcarmo/webterm.git
 cd webterm
-mkdir -p bin
-go build -o ./bin/webterm ./cmd/webterm
+make build-go
 ```
 
-The command above produces `bin/webterm`; you can also build it from repo root with `make build-go`.
+That produces `bin/webterm` and rebuilds generated frontend assets first.
 
 ## Quick start
 
 Run a default shell session:
 
 ```bash
+make build-fast
 go run ./cmd/webterm
 ```
 
 Run a specific command:
 
 ```bash
+make build-fast
 go run ./cmd/webterm -- htop
 ```