Shorten SHM buffer key names to fit Darwin's 31
char filename limit by hashing the `fqme`/content
portion with `md5` and truncating to 8 hex chars.
Deats,
- `.fsp._api`: replace `piker.{actor}[{uuid}].{sym}`
format with `{uuid[:8]}_{hash}.fsp`
- `.tsp._history`: add `platform.system()` check to
conditionally shorten `.hist`/`.rt` keys on Darwin
while keeping the full key format on Linux
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
NOTE that this patch was orig by @dnks and broken out from a larger
commit which added unnecessary/out-of-scope changes we didn't end up
requiring.
Gud Boi
52e65dbe0d