Disable Go and etcd in CI builds

[Copilot]

Description

Removes Go and etcd from all CI workflows to reduce build time and complexity. etcd is not required for CI validation, and Go is only needed for etcd wrapper compilation.

Changes:

• CI Workflows: Removed etcd installation step; set USE_ETCD=OFF and STORE_USE_ETCD=OFF in all CMake configurations
• Release Workflows: Disabled etcd; added CI: "true" env var
• dependencies.sh: Skip Go installation when CI env var is set

Affected workflows:

• ci.yml (main build, build-musa, build-flags jobs)
• ci_cu13.yml
• release.yaml, release-non-cuda.yaml, release-cuda13.yaml

Type of Change

• Types
  • Bug fix
  • New feature
    • Transfer Engine
    • Mooncake Store
    • Mooncake EP
    • Integration
    • P2P Store
    • Python Wheel
  • Breaking change
  • CI/CD
  • Documentation update
  • Other

How Has This Been Tested?

Code review and security scans passed. CI workflows will validate the changes on merge.

Checklist

• I have performed a self-review of my own code.
• I have formatted my own code using ./scripts/code_format.sh before submitting.
• I have updated the documentation.
• I have added tests to prove my changes are effective.

Original prompt

disable go and ectd in ci build

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