fix: bump Go companion image to Go 1.27 (#341)

[antoinetoussaint-byte]

Closes#341.

Summary

• companions/go shipped FROM golang:1.26-alpine at version 0.0.10 (Go 1.26.4). After core v0.3.8 moved services to go 1.27.0, container/Docker-run builds failed under the 1.26 toolchain with toolchain not available — the server never started and the health check reset.
• Bump the Dockerfile to golang:1.27-alpine and info.codefly.yaml to 0.0.11 so golang.CompanionImage() resolves to the Go 1.27 image codeflydev/go:0.0.11.

Publish status

codeflydev/go:0.0.11 was not actually in the registry (contrary to the issue's note — codefly companion verify reported it MISSING). It has now been published as a multi-arch image (linux/amd64 + linux/arm64, go version go1.27.0 confirmed), and codefly companion verify is green for all six companions.

Audit (1.26 → 1.27 drift)

• Other language companions (node, python, codefly, execution) are not Go-based — no drift.
• GoVersion in runners/golang is a caller-supplied passthrough, not a core-owned default — nothing to bump.
• companions/proto builder-stage Dockerfile is still golang:1.26-alpine, but that Dockerfile is a legacy --force-docker fallback — the proto image is actually built from flake.nix (Nix), whose Go comes from nixpkgs, not the Dockerfile. nixpkgs' default go is currently 1.26.5; a real bump means pinning the flake's go → go_1_27 (+ committing a flake.lock for reproducibility, which the flake currently lacks) and republishing codeflydev/proto on amd64. Proto's Go is only swagger's gofmt — it never builds a go 1.27.0 service — so this is cosmetic consistency, not a correctness fix. Deferred to a follow-up (see below).

Follow-ups (separate PRs)

• fix: build a CGO-free CLI so companion publish links statically cli#456 — codefly companion publish couldn't build the go/node/python/base images at all: it cross-compiles the CLI CGO_ENABLED=0, but the CLI linked the tree-sitter (cgo) semantic analyzer unconditionally. That PR makes the CLI CGO-free for the static build. This is why go:0.0.11 was missing — CI/publish couldn't produce it.
• Proto Go 1.27 bump: flake go_1_27 pin + flake.lock + amd64 republish, best done once cli#456 unblocks companion publishing.

Test plan

• go build ./companions/go/
• info.codefly.yaml parses to a valid semver (0.0.11) via golang.version()
• codeflydev/go:0.0.11 published multi-arch; docker run codeflydev/go:0.0.11 go version → go1.27.0; codefly companion verify all-green