gha: build: linux: rework into matrix; use bookworm for .deb builds

[rpardini]

gha: build: linux: rework into matrix; use bookworm for .deb builds

• gha: build: linux: rework into matrix; use bookworm for .deb builds
  • this should reduce the glibc dep version requirement of .deb's, allowing them to run on old but still supported systems
    • See https://v2.tauri.app/distribute/debian/#limitations
      • "you must build your Tauri application using the oldest base system you intend to support"
      • Debian oldstable (Bookworm) will be supported until late 2028, so fair to support it
      • also, there's no downsides; imager itself runs great either way, and .deb install pulls updated deps on newer distros
  • fold linux-x64 and linux-amd64 into a single matrix job (1st level)
  • 2nd matrix level is per-type:
    • deb is now built using an oldtable container
    • appimage is built without container, directly on runner, as before
      • seems like appimage/linuxdeploy doesn't wanna be run in a container
      • also, the AppImage does seem to contain libs, so we don't wanna ship old ones
        Signed-off-by: Ricardo Pardini ricardo@pardini.net
• gha: build: set a specific TAURI_CLI_VERSION (2.9.6)
  • so we can hash it into the cache keys (done in later commit) for consistency
    Signed-off-by: Ricardo Pardini ricardo@pardini.net
• gha: build: linux: rework caching for consistency
  • actions/setup-node doesn't allow for setting cache keys
    • even in recent versions... (bumped to v6)
    • so move npm caching to actions/cache:
      • disable setup-node caching via package-manager-cache: false
      • add new step for actions/cache "npm dependencies"
        • cache key includes the runner image, the container distro (if any), and hash of package-lock.json
  • for Swatinem/rust-cache
    • use a cache key that includes the runner image, the container distro (if any), and TAURI_CLI_VERSION
    • add a TODO ref Cargo.lock missing/.gitignored, as it would be hashed too automatically had it existed
  • for actions/cache based "cargo bin tauri-cli" caching
    • use a cache key that includes the runner image, the container distro (if any), and TAURI_CLI_VERSION
    • also TODO ref Cargo.lock, which was spelled out, but doesn't exist
    • also TODO as it seems to me this is already covered by the Swatinem/rust-cache cache
      Signed-off-by: Ricardo Pardini ricardo@pardini.net