fix(processors): log actual page count being processed, not document total

Objective: When users pass --pages with values that are out of range
(e.g. --pages 99999 on a 15-page PDF), warnings correctly report that
no pages will be processed, but the same run also logs "Processing 15
pages with 1 threads". Users reading the log cannot tell whether
processing actually happened or not, and the contradiction between
WARN and INFO lines undermines trust in every other log message.

Approach: In DocumentProcessor.processDocument, switch the INFO log to
report the size of pagesToProcess (the validated set) instead of the
document's total page count. When pagesToProcess is null (no --pages
filter), fall back to totalPages so full-document runs still report
correctly. This is the smallest change that resolves the contradiction;
the surrounding behavior (exit code, empty-output handling, range
auto-clamp asymmetry) is left alone — those belong to separate
discussions about CLI validation policy, not log accuracy.

Evidence: Built the CLI and ran 5 scenarios against a 15-page PDF
(samples/pdf/1901.03003.pdf).

| Scenario               | Before          | After           |
|------------------------|-----------------|-----------------|
| no --pages             | "Processing 15" | "Processing 15" |
| --pages 99999          | "Processing 15" | "Processing 0"  |
| --pages 1,99999        | "Processing 15" | "Processing 1"  |
| --pages 1-5            | "Processing 15" | "Processing 5"  |
| --pages 22-30          | "Processing 15" | "Processing 0"  |

The log now matches the WARN message and the actual JSON output content.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: bundolee

java/opendataloader-pdf-core/src/main/java/org/opendataloader/pdf/processors/DocumentProcessor.java

@@ -283,7 +283,8 @@ private static List<List<IObject>> processDocument(String inputPdfName, Config c
 
         int parallelism = config.getThreads();
         ForkJoinPool pool = new ForkJoinPool(parallelism);
-        LOGGER.log(Level.INFO, "Processing {0} pages with {1} threads", new Object[]{totalPages, parallelism});
+        int pagesToProcessCount = (pagesToProcess != null) ? pagesToProcess.size() : totalPages;
+        LOGGER.log(Level.INFO, "Processing {0} pages with {1} threads", new Object[]{pagesToProcessCount, parallelism});
 
         try {
             // Loop 1: ContentFilter per-page (largest bottleneck)