Caption detection was incorrectly classifying "Table of Contents" as a
caption because it starts with "Table ". Now "Table" and "Figure"
prefixes require a digit, parenthesis, or hash after them — matching
actual captions like "Table 1", "Figure 3.2" but not titles.
Also removes debug logging left from previous iteration.
Benchmark improvement: MHS 0.52→0.54, overall 0.757→0.761.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>