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.

tests/test_verify_pdf.py

@@ -106,6 +106,39 @@ class FindNonAsciiDateRangesTests(unittest.TestCase):
             with self.subTest(text=text):
                 self.assertEqual(find_non_ascii_date_ranges(text), [])
 
+    def test_numeric_range_with_year_shaped_ends_is_a_quantity_not_a_date(self):
+        # Four-digit numbers that are not both years: #512 bounded the year but
+        # a salary band or a throughput range still read as a date range.
+        for text in (
+            "Salary EUR 1500\u20132000 per month",
+            "Scaled the API to serve 2000\u20135000 requests per second",
+            "Grew users from 2000\u20135000",
+            "Budget 1.5\u20132.0M, headcount 20\u201325",
+        ):
+            with self.subTest(text=text):
+                self.assertEqual(find_non_ascii_date_ranges(text), [])
+
+    def test_numerically_formatted_date_ranges_are_still_caught(self):
+        # A composite token (slashed, dotted, hyphenated) is not a bare number,
+        # so the quantity rule does not apply and the year rule still fires.
+        # These are the Workday-drops-the-date shape the flag exists for.
+        for text in (
+            "03/2016\u201307/2024",
+            "01.2016 \u2013 12.2024",
+            "2016-03\u20132024-07",
+            "2016/17\u20132018/19",
+            "2016/03\u20132024/07",
+            "01.03.2016\u201331.07.2024",
+            "2016\u201307/2024",
+        ):
+            with self.subTest(text=text):
+                self.assertEqual(len(find_non_ascii_date_ranges(text)), 1)
+
+    def test_two_years_joined_by_a_dash_are_still_a_date_range(self):
+        for text in ("2016\u20132024", "1990\u20132010 programme", "Roles 2000\u20132024"):
+            with self.subTest(text=text):
+                self.assertEqual(len(find_non_ascii_date_ranges(text)), 1)
+
     def test_a_standalone_year_next_to_a_longer_number_is_still_caught(self):
         self.assertEqual(find_non_ascii_date_ranges("2016\u20132024 (120000 users)")[0][1], "\u2013")