[SYSTEMDS-3959] Report an error when a federated worker cannot bind its port

[gaturchenko]

The command systemds WORKER 80505 terminated silently with exit code 0. There are 2 causes:

1. No range check for -w <port>
2. FederatedWorker.run() captured every exception in a catch-all. The same held for occupied and reserved ports, and for the -fedMonitoring backend

The following changes were implemented:

• PortUtils (new): shared port validation plus explainBindFailure, which turns terse socket errors into messages naming the port and the cause.
• DMLOptions: -w and -fedMonitoring reject non-integers and ports outside [1, 65535]. A missing (optional) -w argument now falls back to the default port instead of throwing NumberFormatException.
• FederatedWorker / FederatedMonitoringServer: reject out-of-range ports upfront, warn on reserved ports (< 1024), and throw bind failures as DMLRuntimeException after logging.
• bin/systemds: the duplicated WORKER/FEDMONITORING check is now one checkPort function with a range check and exit 1. Previously, an error was printed and the JVM was launched regardless.

[codecov]

Codecov Report

❌ Patch coverage is 47.16981% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.43%. Comparing base (9dccbc3) to head (1362487).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...rc/main/java/org/apache/sysds/utils/PortUtils.java	42.30%	10 Missing and 5 partials ⚠️
...ederated/monitoring/FederatedMonitoringServer.java	15.38%	7 Missing and 4 partials ⚠️
...time/controlprogram/federated/FederatedWorker.java	71.42%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2586      +/-   ##
============================================
- Coverage     71.44%   71.43%   -0.01%     
- Complexity    50437    50444       +7     
============================================
  Files          1629     1630       +1     
  Lines        195513   195559      +46     
  Branches      38118    38128      +10     
============================================
+ Hits         139686   139703      +17     
- Misses        44867    44877      +10     
- Partials      10960    10979      +19     

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