Enhance release/build pipeline, add Linux slim build and binary compression; fix small Go process/session issues

[YspCoder]

Motivation

• Improve the GitHub release workflow to produce reproducible per-platform artifacts and checksums while keeping Linux builds slimmer without disabling channel capabilities.
• Provide Makefile knobs for slimmer/ultra-slim builds and optional binary compression for smaller release artifacts.
• Fix minor Go issues (no-op assignments and un-cancelled contexts) to avoid leaks and clean up code.

Description

• Replace the single make build-all step in .github/workflows/release.yml with explicit per-target go build steps, add make sync-embed-workspace/cleanup, separate Linux builds with special flags, and generate per-target .tar.gz/.zip packages plus checksums.txt.
• Extend the Makefile with new variables (BUILD_FLAGS, COMPRESS_BINARY, UPX_FLAGS, LINUX_SLIM_*), default -trimpath -buildvcs=false, optional upx compression, a new build-linux-slim target, and updated build, build-all, and package-all flows to support these options.
• Update README.md and README_EN.md to document make build-linux-slim, COMPRESS_BINARY=1 usage, and ultra-slim build notes.
• Fix Go code in pkg/tools/process_manager.go, pkg/tools/sessions_tool.go, and pkg/nodes/registry_server.go by removing redundant no-op assignments and adding cancel() calls when StdoutPipe/StderrPipe creation fails to avoid leaking contexts.

Testing

• Ran go test ./... which completed successfully.
• Performed local builds using make build-linux-slim and make build-all and confirmed binaries are produced in build/ and packaging via make package-all generated .tar.gz/.zip files and build/checksums.txt.
• Verified that make build COMPRESS_BINARY=1 attempts upx compression and that builds succeed when upx is not present (skips with warning).

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Codex Task