fix: simplify region text extraction to trust layout model ordering

When fire-pdf sends pre-segmented bboxes from the layout model,
pdf-inspector no longer runs column detection, stream-order heuristics,
or newspaper/tabular mode detection within the region. These heuristics
conflict with the layout model's decisions and cause wrong reading order.

Region extraction now simply: Y-sorts items, groups into lines, and
sorts within each line by X position. The heavy heuristics remain
available for standalone full-page extraction.

Eval showed pure OCR (0.2875 NED) beating native+heuristics (0.2916)
across all categories, especially multi-column (-0.08) and newspaper
(-0.16). This change should close that gap.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

napi/Cargo.lock

@@ -129,12 +129,6 @@ version = "3.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
 
-[[package]]
-name = "bytecount"
-version = "0.6.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "175812e0be2bccb6abe50bb8d566126198344f707e304f45c648fd8f2cc0365e"
-
 [[package]]
 name = "cbc"
 version = "0.1.2"
@@ -679,7 +673,7 @@ checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 [[package]]
 name = "lopdf"
 version = "0.40.0"
-source = "git+https://github.com/J-F-Liu/lopdf?rev=052674053814a9f4897af94f0b8e46a545c9b329#052674053814a9f4897af94f0b8e46a545c9b329"
+source = "git+https://github.com/J-F-Liu/lopdf?rev=7a05512d831415b1f2b1ce522391d6beab8a1284#7a05512d831415b1f2b1ce522391d6beab8a1284"
 dependencies = [
  "aes",
  "bitflags",
@@ -695,7 +689,6 @@ dependencies = [
  "log",
  "md-5",
  "nom",
- "nom_locate",
  "rand",
  "rangemap",
  "rayon",
@@ -807,17 +800,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "nom_locate"
-version = "5.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b577e2d69827c4740cba2b52efaad1c4cc7c73042860b199710b3575c68438d"
-dependencies = [
- "bytecount",
- "memchr",
- "nom",
-]
-
 [[package]]
 name = "num-conv"
 version = "0.2.1"