fix(build): disable CGO for darwin builds in goreleaser

CGO cross-compilation for darwin from Linux CI runner fails without
osxcross. Since Dolt/federation features are now CGO-optional,
darwin builds can use CGO_ENABLED=0.

Users who need Dolt features on macOS can build from source with
CGO enabled.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.goreleaser.yml

@@ -61,7 +61,7 @@ builds:
     main: ./cmd/bd
     binary: bd
     env:
-      - CGO_ENABLED=1
+      - CGO_ENABLED=0
     goos:
       - darwin
     goarch:
@@ -77,7 +77,7 @@ builds:
     main: ./cmd/bd
     binary: bd
     env:
-      - CGO_ENABLED=1
+      - CGO_ENABLED=0
     goos:
       - darwin
     goarch: