Add CI workflow: multi-platform release builds, artifact upload, and tag-triggered GitHub Releases

[Copilot]

Adds a GitHub Actions CI workflow that builds the binary in release mode for multiple platforms on every push and publishes all binaries to GitHub Releases on tag pushes.

Workflow triggers

• All branch pushes: build + upload artifacts
• Tag pushes (v*): build + upload artifacts + create/publish GitHub Release

Build matrix

Runner	Rust Target	Binary Name
ubuntu-latest	x86_64-unknown-linux-gnu	pixivdwn-x86_64-unknown-linux-gnu
ubuntu-24.04-arm	aarch64-unknown-linux-gnu	pixivdwn-aarch64-unknown-linux-gnu
windows-latest	x86_64-pc-windows-msvc	pixivdwn-x86_64-pc-windows-msvc.exe
windows-latest (cross)	aarch64-pc-windows-msvc	pixivdwn-aarch64-pc-windows-msvc.exe

Steps

• Linux: installs libsqlite3-dev via apt (required by sqlx's sqlite-unbundled feature)
• Windows: installs sqlite3 via vcpkg using the appropriate static triplet (x64-windows-static-md / arm64-windows-static-md)
• cargo build --release --target <target>
• Renames each binary to include its Rust target triple as the platform/ABI identifier
• Uploads each binary as a named per-target Actions artifact
• On tag push: uses softprops/action-gh-release (pinned to commit SHA) to create the release if absent and attach all four binaries

Security

softprops/action-gh-release is pinned to a specific commit SHA (c062e08b) rather than a mutable tag to guard against supply chain attacks.

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[CircuitCoder]

@copilot This is a native binary. Please also add Windows build, as well as arm64 builds. Uploaded binaries should have their platforms and ABIs noted in their filenames.

[Copilot]

@copilot This is a native binary. Please also add Windows build, as well as arm64 builds. Uploaded binaries should have their platforms and ABIs noted in their filenames.

Done in 44cb0e0. The workflow now builds a matrix of four targets:

Runner	Target	Artifact name
ubuntu-latest	x86_64-unknown-linux-gnu	pixivdwn-x86_64-unknown-linux-gnu
ubuntu-24.04-arm	aarch64-unknown-linux-gnu	pixivdwn-aarch64-unknown-linux-gnu
windows-latest	x86_64-pc-windows-msvc	pixivdwn-x86_64-pc-windows-msvc.exe
windows-latest (cross)	aarch64-pc-windows-msvc	pixivdwn-aarch64-pc-windows-msvc.exe

Linux builds use libsqlite3-dev from apt; Windows builds use vcpkg with the appropriate static triplet (x64-windows-static-md / arm64-windows-static-md). All four binaries are uploaded as artifacts and, on v* tag pushes, attached to the GitHub Release.