docrot-api v1.5.0 — CommonMark inline-code span pairing

Parity with the open-source scanner v7 (docrot v1.5.1/v1.5.2): inline code spans now pair by equal backtick-run length, paragraph-locally, instead of positionally. Found by manually verifying a scanner false positive on a real 68 KB document whose code-span image example GitHub renders as plain <code> — the API would have live-checked it into a false broken verdict. The paragraph-local rule also closes the triple-newline separator edge. Line-number provenance unchanged (blanked spans keep their newlines). Suite 124 green.