#157 stage 3 (phase 2): expose resample + tf_match under ocr-prep

Both modules are already pure Rust (resample uses only `image`; tf_match
only std) but were gated behind `ml`. Re-gate them to ocr-prep and make
tf_match a public module so the browser TableFormer path (phase 3) can
crop table regions (page→1024px box-average, crop→448 bilinear) and run
docling's cell matcher — the same code the native pipeline uses. Native
`ml` still pulls them in (ocr-prep ⊂ ml); the ocr-prep-only slice now
compiles both. No behavior change.

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-pdf/src/lib.rs

@@ -31,7 +31,9 @@ mod ocr;
 pub mod ocr_prep;
 pub mod pdfium_backend;
 mod reading_order;
-#[cfg(feature = "ml")]
+// Pure-Rust region resampling (page→1024px box-average, crop→448 bilinear) —
+// available to the browser TableFormer path (#157 stage 3), not just `ml`.
+#[cfg(feature = "ocr-prep")]
 pub mod resample;
 #[cfg(feature = "ocr-prep")]
 pub mod scanned;
@@ -40,8 +42,10 @@ pub mod tableformer;
 #[cfg(feature = "ocr-prep")]
 pub mod tf_core;
 pub mod textparse;
-#[cfg(feature = "ml")]
-mod tf_match;
+// docling's TableFormer cell matcher — pure Rust, shared with the browser
+// TableFormer path (#157 stage 3).
+#[cfg(feature = "ocr-prep")]
+pub mod tf_match;
 pub mod timing;
 
 #[cfg(feature = "ml")]