fix: sleep in inner per-file loop and missing exit on error

[k-rister]

Bugs Found

1. Sleep inside inner loop (HIGH)

procstat-collect line 44: sleep $interval is inside the for file in $good_files loop. With 7 files and a 3s interval, each file is sampled every 21s instead of every 3s. The sleep should be after the inner done.

2. Missing exit 1 after error (HIGH)

procstat-start line 68: Missing exit 1 after the error message about a missing binary — the script falls through and exits 0 (success), masking the failure.

3. Wrong filename in rm command (MEDIUM)

procstat-start line 57: rm -f procstat-pids.txt (plural) but the actual file created is procstat-pid.txt (singular). The cleanup never removes the intended file.

4. Typos (LOW)

• procstat-stop line 19: procstst-pid.txt (should be procstat-pid.txt)
• procstat-start line 39: Invalid optioni (should be Invalid option)
• procstat-collect line 8: must a be a positive interger (should be must be a positive integer)