Blind sleeps accumulate serially (no t.Parallel anywhere) and inflate
under the race detector's scheduling overhead — contributing to the
~136s channelserver test run time.
Replace ~75 arbitrary sleeps (50ms–1s) across 7 test files with 2s
polling loops that exit as soon as the expected condition holds. Sleeps
that are genuinely intentional (race-condition stress tests, cache
expiry, temporal spacing in timestamp tests, backpressure pacing) are
left untouched.
Fix unchecked error returns on bf.Seek(), db.Exec(), QueryRow().Scan(),
pkt.Build(), logger.Sync(), and binary.Write() calls. The linter now
passes with 0 errors, build compiles, and all tests pass with -race.
