Test servers shut down without the 0.5s poll wait, unit tests refuse non-loopback lookups, and three load-sensitive tests are steadied. Pushes to dev test Python 3.11 only; the docs job builds with uv.
Renames 314 defs and 41 module/class-level constants. Keeps 11 names underscored where the stripped form collides in scope, plus 5.5.0 shims for the three symbols external service repos call.
Any batch failure sets the process-global DOWNLOAD_CANCELLED, which
TokenBucket.consume waits on, so a test elsewhere could void every timing
assertion here; add the autouse clear fixture the other downloader test
modules already use. Also capture the debt sleep via a stub instead of
timing a real Event.wait, whose occasional spurious early wake tripped the
1.0s lower bound.