Review feedback: publishing the map and its platform tag as two separate
global assignments is not atomic. A reader landing between them sees the
NEW map still carrying the OLD tag, and if that stale tag matches its own
platform it accepts the map without rescanning — serving another
platform's disabled-skill view, the leak #14536 closed.
Guard the pair with a module lock. scan_skill_commands publishes both
under it; get_skill_commands resolves its platform first, then reads the
map and tag together under the same lock to make the freshness decision.
Scanning stays outside the lock — it does file I/O and deferred imports,
and concurrent scans are already independent after the local-map change.
get_skill_commands now returns the scan's own completed map rather than
re-reading the global, so a concurrent publish cannot swap the result
between the decision and the return.
Adds a regression test that holds the publish lock and asserts a reader
cannot complete its lookup until it is released.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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