fix(verify_pdf): --ascii-dates treats a numeric range as a date only when both ends are bare years (#533)

month" and "2000-5000 requests per second" still failed /apply Step 5d:
each has a four-digit number next to the dash that happens to fall in
1900-2099, and the guide tells users to keep "--" in exactly those
prose ranges.

When both sides of the dash are bare numbers - the whole
whitespace-delimited token, outer punctuation stripped, matching
\d+(?:[.,]\d+)*[kKmM%]? with no year group among its parts - count the
match only if both are years. The salary band and the throughput range
pass; 2016-2024, 1990-2010 and "2016 - Present" still fail as before,
and a numerically formatted range (03/2016-07/2024, 01.2016 - 12.2024,
2016-03-2024-07, 2016/17-2018/19) is not a bare number on either side
and is still caught. On the stock CV with all three prose ranges on one
line, master reports three hits and this branch reports the one real
date.

Three new cases; the quantity one fails on master.

CHANGELOG.md

@@ -68,6 +68,17 @@ per-file diff commands.
 
 ### Fixed
 
+- **`verify_pdf.py --ascii-dates` no longer reads a numeric range with year-shaped ends as a
+  date** - #512 bounded the year to four standalone digits, but `EUR 1500–2000 per month` and
+  `2000–5000 requests per second` still failed `/apply` Step 5d: each has a four-digit number
+  next to the dash that happens to fall in 1900-2099. A range whose two ends are both bare
+  numbers (the whole whitespace-delimited token, outer punctuation stripped) now counts as a
+  date only when both are years, so the salary band and the throughput range pass, while
+  `2016–2024`, `1990–2010` and `2016 – Present` still fail as before and a numerically
+  formatted range (`03/2016–07/2024`, `01.2016 – 12.2024`, `2016-03–2024-07`, `2016/17–2018/19`)
+  is not a bare number on either side and is still caught. Three new `test_verify_pdf.py`
+  cases; the quantity one fails on master.
+
 - **`upstream_triage` forces UTF-8 stdout and decodes git output as UTF-8** (#544,
   `tools/upstream_triage.py`, `tests/test_tools_utf8_output.py`) - like the other Python tools,
   the triage report now calls `_force_utf8_output()` on startup and decodes git subprocess