Add local release Makefile

[kuliantnt]

Summary

Add a small Makefile for local development and release workflows.

Changes

• Add default help output for available targets.
• Add fmt, fmt-check, clippy, test, check, build, and release targets.
• Add install-local for installing the release binary to $(HOME)/.local/bin.
• Add tag helper for the current Cargo package version.

Verification

• make
• make fmt-check
• make release
• cc-switch --version => cc-switch 0.1.4

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