fix: skip linux/arm64 binary builds to avoid CGO cross-compilation

Problem:
- linux_amd64 runner was trying to build BOTH:
  - linux/amd64 (native - OK)
  - linux/arm64 (cross-compile with CGO - FAILS)
- Error: gcc_arm64.S assembler errors when cross-compiling ARM64 on x86_64
- Workflow default platforms only include linux/amd64, not linux/arm64

Solution:
- Added linux/arm64 to ignore list in both builds
- Only build linux/amd64 binaries (native compilation on ubuntu-latest)
- Docker images still provide linux/arm64 via multi-stage builds
- Users get ARM64 support through Docker, not standalone binaries

Build matrix now:
- ✅ darwin/arm64 (macOS Apple Silicon) - native on macos-latest
- ✅ linux/amd64 (Linux x86_64) - native on ubuntu-latest
- ❌ linux/arm64 (skipped for binaries, available in Docker)

This eliminates CGO cross-compilation while maintaining full platform support
via Docker multi-arch images.

.goreleaser.yaml

@@ -39,6 +39,8 @@ builds:
     ignore:
       - goos: darwin
         goarch: amd64
+      - goos: linux
+        goarch: arm64  # Skip linux/arm64 binaries (Docker handles multi-arch)
 
   - id: migrate
     main: ./cmd/migrate
@@ -63,6 +65,8 @@ builds:
     ignore:
       - goos: darwin
         goarch: amd64
+      - goos: linux
+        goarch: arm64  # Skip linux/arm64 binaries (Docker handles multi-arch)
 
 # Archives for releases
 archives: