Backpack Runtime v0.2.0-alpha.7

Backpack Runtime v0.2.0-alpha.7

This prerelease fixes Windows self-update activation. It otherwise contains the
same Cloud coding-agent hardening and qualification delivered in alpha.6.

Install or recover from an alpha.6 staged-update error

irm https://backpack.run/install.ps1 | iex

The installer independently verifies the release checksum and replaces the
installed binary. Users who encountered verified staged update already exists
do not need to run or trust the abandoned side-by-side executable.

Fix

• Windows updates now rename the currently mapped executable to a timestamped
  rollback backup and activate the verified replacement before the update
  command exits.
• A legacy target-specific .update-* file from alpha.6 or earlier is removed
  safely instead of making every retry fail.
• The activation path retains rollback behavior if replacing the executable
  fails after the backup rename.

Windows amd64 remains the supported alpha platform. Linux amd64 and macOS arm64
remain previews. Cloud and coding-agent integrations remain experimental.