## change: `.spt` adapter packages can pack all platforms
- the issue: when an adapter manifest chooses to update via GH releases, SPT looks for a single `adapter.spt` release artifact. this is problematic for multi-OS adapters, because the current `.spt` archive format only accounts for one OS at a time/per-archive.
- proposal: enable adapter updates/installers to package linux, windows, and any future supported platforms all inside the .spt file.
  - larger adapters may prefer to split by platform (and they still can, with this change), but this will be a helpful feature for adapters with a smaller filesize + better installation UX

+ also, `spt adapter update` should only replace files that have a different CRC vs. the existing ones
++ also, `spt adapter update` must stop the adapter's binaries (IMTB, psyche, etc.) before it updates them, then restart them. this way, endpoints running a given adapter can update live without restarting the whole endpoint
+++ support an `update-message` string defined in adapter manifests-->is then surfaced to stdout anytime `spt adapter update` is run. for instance, `spt-claude-code` might have a message like "Don't forget to run `/reload-plugins` in any ongoing sessions."