ci: replace manual release workflow with cargo-dist

[lwshang]

Why

The Release workflow fails on every run: it pinned actions/upload-artifact and actions/download-artifact at v3, which GitHub now automatically hard-fails. The workflow also targeted the retired ubuntu-20.04 runner.

Rather than patch the hand-rolled workflow, this adopts cargo-dist (v0.31.0), following the setup already in use in dfinity/ic-wasm.

What

• dist-workspace.toml (new) — mirrors ic-wasm: ci = "github", shell installer, install-updater = true, and a [dist.github-action-commits] block that pins all generated uses: lines to full commit SHAs (matches our security policy).
• Cargo.toml — adds the repository field (required by dist) and [profile.dist].
• .github/workflows/release.yml — regenerated by dist generate; replaces the manual plan/build/test/publish jobs.

Target platforms

Built on native runners (so system OpenSSL is available — no cross-compile/vendoring):

Target	Runner
x86_64-unknown-linux-gnu	ubuntu-22.04
aarch64-unknown-linux-gnu	ubuntu-22.04-arm
x86_64-apple-darwin	macos-15-intel
aarch64-apple-darwin	macos-14

Behavioral changes

• Release artifacts are now .tar.xz archives named by target triple, plus an install script + checksums (not the old bare ic-repl-linux64 / ic-repl-macos / ic-repl-arm32 binaries).
• The 32-bit arm-unknown-linux-gnueabihf build is dropped, replaced by 64-bit aarch64. The [target.arm-unknown-linux-gnueabihf] openssl block in Cargo.toml is left in place (inert in CI, preserves local arm32 cross-builds).
• Triggers on semver-style tags (**[0-9]+.[0-9]+.[0-9]+*); the existing 0.7.8-style convention still matches. Runs a no-publish dist plan on PRs.

Verification

• dist generate --check passes (exit 0) — the committed release.yml is byte-identical to dist 0.31.0's output, so it won't drift.
• dist plan resolves the matrix above; all targets are native builds.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR replaces the repo’s hand-rolled GitHub Actions release workflow with a cargo-dist–generated workflow to fix failures caused by deprecated Action versions and runner retirement, and to standardize release artifact generation.

Changes:

• Add dist-workspace.toml to configure cargo-dist (including pinning GitHub Actions uses: to commit SHAs).
• Update Cargo.toml with the repository field required by cargo-dist and add a [profile.dist].
• Regenerate .github/workflows/release.yml via dist generate, replacing the prior manual build/test/publish jobs.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
dist-workspace.toml	Introduces cargo-dist workspace configuration and pins GitHub Actions to commit SHAs.
Cargo.toml	Adds repository metadata and a dist-specific release profile.
.github/workflows/release.yml	Replaces the manual release workflow with the cargo-dist–generated plan/build/host pipeline.

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