wasm scan: log the layout region-label histogram

Diagnostic for the browser scanned path: console-log the per-page region
labels after refinement, so it's visible whether the layout flagged any
`table` region — a scanned table only fills when it does and the region's
words are OCR'd (a known gap: prep_region_lines skips non-text labels, so
table interiors currently carry no words for the matcher).

Refs #157

Signed-off-by: artiz <artem.kustikov@gmail.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EY5KAiquN4YpVf2PXEQkVT

Author: artiz

crates/docling-wasm/src/scanned.rs

@@ -33,6 +33,12 @@ use wasm_bindgen::prelude::*;
 use crate::ocr::{tensor_parts, RecSession};
 use crate::tableformer::TfSession;
 
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(js_namespace = console, js_name = log)]
+    fn console_log(s: &str);
+}
+
 #[wasm_bindgen]
 extern "C" {
     /// The JS-side layout session: a wrapper around an `ort.InferenceSession`
@@ -145,6 +151,19 @@ impl ScannedConverter {
         let regions = decode_layout(&logits, &boxes, q, c, page_w, page_h);
         let regions = refine_regions(regions, &[], page_w, page_h);
 
+        // Diagnostic: the region-label histogram, so it's visible (browser
+        // console) whether the layout model flagged any `table` region on this
+        // page — tables only render when it does (geometric or TableFormer).
+        {
+            let mut hist: std::collections::BTreeMap<&str, usize> =
+                std::collections::BTreeMap::new();
+            for r in &regions {
+                *hist.entry(r.label).or_default() += 1;
+            }
+            let summary: Vec<String> = hist.iter().map(|(l, n)| format!("{l}×{n}")).collect();
+            console_log(&format!("layout regions: {}", summary.join(", ")));
+        }
+
         // OCR the text regions (same gather/batch/decode as native ocr_page).
         let (bboxes, lines) = prep_region_lines(&img, &regions, scale);
         let mut texts = vec![String::new(); lines.len()];