Fix rand.Seed initialization and data races in progress bars

[msarg44]

Two fixes for correctness issues:

1. Add rand.Seed(time.Now().UnixNano()) in init()

The project declares go 1.16 and uses rand.Shuffle() in IPCIDR() and IPWildcard() for non-sequential mode. Go 1.16–1.19 require explicit seeding via rand.Seed() — without it, the shuffle produces identical ordering every run, defeating the purpose of !seqMode.

2. Fix data races in progress bar routines

ProgressBar() and RejectAllOpenProgressBar() read shared counters (doneCount, hostUpCount, openCount, hostDiscard, stopRejectAllOpenProgressBar) without holding the mutex that protects writes to these variables in worker goroutines. This is a data race per the Go memory model.

Changes:

• ProgressBar(): local copies of counters under mutex lock before logging
• RejectAllOpenProgressBar(): same treatment for counters, plus stopRejectAllOpenProgressBar reads under mutex

Both fixes verified to compile with go 1.16 through current Go versions.

[L-codes]

Thanks for submitting, but the counting variable name will simply retain the original name to improve readability.