feat: multi-image runners — go, node, docker, deploy, godot

Replace single fat image with purpose-built images per workflow type.
Each image is lean: base (Alpine+AWS+git) → go/node/deploy extend it.
docker image standalone (dind base). godot for future game builds.
build-all.sh builds base first, then all others in parallel.

images/go/Dockerfile

@@ -0,0 +1,15 @@
+# tinqs/ci go — Go builds (platform, CLI, proxy)
+# Used by: build-tstudio, deploy-proxy
+# runs-on: go
+
+ARG BASE_IMAGE=tinqs-runner-base:latest
+FROM ${BASE_IMAGE}
+
+ARG GO_VERSION=1.26.2
+
+RUN curl -fsSL "https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz" | tar -C /usr/local -xz
+
+ENV PATH="/usr/local/go/bin:/go/bin:${PATH}"
+ENV GOPATH="/go"
+
+RUN go version