[andreatnvidia]

Superseded by #1134, which now includes this fix and its regression tests.

Summary

Generated phone numbers could contain a four-digit exchange (1000) or a five-digit line number (10000) because randint includes its upper bound. Correct both ranges and resample N11 exchanges, which NANPA lists as unavailable for assignment.

Related Issue

Found during review of #1134. Kept separate from that data-provenance change.

Changes

• Generate exchange codes from 200 through 999 and skip values ending in 11.
• Generate line numbers from 0000 through 9999.
• Add public-method regression tests for both range boundaries and all eight N11 exchanges.

Testing

• Sampling suite: 263 passed.
• Parameterized boundary and N11 tests added.
• Changed Python files pass Ruff lint/format checks.
• Full repository suite and E2E tests were not run.

Checklist

• Follows commit message conventions.
• Commit is signed off (DCO).
• External contributor issue requirement: N/A.
• Architecture docs: N/A.