fix(release): Enable CGO for tree-sitter, limit to linux/amd64

The go-tree-sitter dependency requires CGO (C bindings). Cross-compilation
with CGO_ENABLED=0 fails on the GitHub Actions runner. Limit the initial
0.1.0 release to linux/amd64 (native on the runner). macOS and Windows
builds will be added in a follow-up with cross-compiler toolchains.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pmclSF

.goreleaser.yaml

@@ -6,14 +6,11 @@ builds:
   - main: ./cmd/terrain
     binary: terrain
     env:
-      - CGO_ENABLED=0
+      - CGO_ENABLED=1
     goos:
       - linux
-      - darwin
-      - windows
     goarch:
       - amd64
-      - arm64
     ldflags:
       - -s -w
       - -X main.version={{.Version}}