chore: remove cgo since we removed pg_query_go

[tianzhou]

No description provided.

[Copilot]

Pull Request Overview

This PR removes CGO dependencies from the build process following the removal of the pg_query_go dependency. The changes simplify the build configuration by eliminating CGO-specific tooling and switching to native Go cross-compilation.

Key Changes:

• Removed CGO build tools (gcc, g++, musl-dev) and runtime dependencies (libc6-compat) from Docker configuration
• Replaced Docker-based cross-compilation with native Go cross-compilation in CI workflows
• Updated documentation to reflect CGO-free build commands

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
Dockerfile	Removed CGO build dependencies and runtime libraries, disabled CGO_ENABLED flag
CLAUDE.md	Removed CGO_ENABLED=1 from build command documentation
.github/workflows/release.yml	Replaced Docker/QEMU-based builds with native Go cross-compilation

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