Group G: sysup upgrade coverage for new toolchains

[thompsonson]

Closes a functional gap in sysup upgrade. Today it handles brew upgrade / apt upgrade; the new toolchains introduced in groups #26–#31 each have their own upgrade paths and silently drift otherwise.

Changes to dot_local/bin/executable_sysup

Extend the upgrade command with handlers, each gated on the matching command -v check and relevant install_* data flag. Ordered by cost (cheapest first) so a sysup upgrade under time pressure can Ctrl-C mid-run without missing the cheap wins.

Rust (rustup)

if command -v rustup >/dev/null 2>&1; then
  echo "==> rustup"
  rustup update
fi

Nix profile (devenv, cloud-hypervisor, virtiofsd)

if command -v nix >/dev/null 2>&1; then
  echo "==> nix profile"
  nix profile upgrade '.*'
fi

Cargo-installed binaries (tauri-cli, create-tauri-app, any future cargo install)

Requires cargo-update to be installed; add cargo install cargo-update --locked to the Rust bootstrap (#28) or install on first upgrade run.

if command -v cargo-install-update >/dev/null 2>&1; then
  echo "==> cargo install-update"
  cargo install-update -a
fi

Google Cloud components

if command -v gcloud >/dev/null 2>&1; then
  echo "==> gcloud components"
  gcloud components update --quiet
fi

Android SDK (opt-in only)

Gated on {{ if .install_android }} and [ -d "$HOME/Android/Sdk" ]:

if command -v sdkmanager >/dev/null 2>&1; then
  echo "==> Android SDK"
  sdkmanager --update
fi

Also touch sysup status

The status command should show outdated counts for each of these too — minimally, call rustup check, nix profile list with a staleness heuristic, and gcloud components list --filter='state.name=Update Available'. If that's more than a line or two per tool, defer to a follow-up; the upgrade path is the priority.

Verification checklist

• sysup upgrade on a machine with only apt/brew tools works identically to today (no new errors from missing binaries).
• sysup upgrade on a machine with nix+rustup+gcloud runs all five new handlers in order.
• Ctrl-C mid-run leaves the system in a consistent state (each handler is atomic enough).
• sysup upgrade with install_android=false does not attempt sdkmanager.
• sysup doctor still reports correct versions after an upgrade.

Related

• Depends on Group A: Nix + devenv bootstrap (Linux-first) #26 (Group A, Nix), Group B: microVM sandbox host prep (Linux only, depends on A) #27 (Group B, microVM Nix packages), Group C: Rust toolchain (rustup) #28 (Group C, Rust), Group D: Tauri CLI + system libs (depends on C) #29 (Group D, Tauri), Group E: Google Cloud SDK (gcloud) #30 (Group E, gcloud), Group F: Android SDK (opt-in, heavy) #31 (Group F, Android SDK).
• Not blocked by any — can implement each handler as its feature group lands, merging the sysup change in a single PR once at least A and C are in.