relax table extraction validation for layout-assisted regions (0.4.3)

Two changes that reduce false needsOcr rejections without hurting quality:

1. Per-region GID check instead of per-page blanket rejection.
   Previously, if ANY font on the page used GID-encoded glyphs (common
   in logos, decorative fonts), ALL table and text regions on that page
   were forced to GPU OCR via needsOcr=true. Now the page-level bail is
   removed; per-region text quality checks (is_garbage_text, is_cid_garbage,
   detect_encoding_issues) catch actual GID corruption in the extracted
   content. Tables whose text is clean pass through even if an unrelated
   font elsewhere on the page is GID-encoded.

2. Relaxed looks_like_partial_table for layout-assisted extraction.
   When the layout model already identified a region as a table (i.e.,
   extract_tables_in_regions_mem), boundary-detection heuristics are
   less necessary — we're not guessing "is this a table?" anymore, only
   "can we extract it correctly?". Relaxations:
   - Numeric first header cell accepted (e.g., year "2024")
   - 1 empty header cell allowed in 3+ column tables (merged headers)
   - Sparse first data row threshold relaxed from 33% to 50%
   Paragraph detection and duplicate-header checks remain strict.

Eval: 196/196 pass (full regression suite), 91/91 Rust tests pass
including 7 new layout-assisted validation tests. Zero regressions.

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

napi/package.json

@@ -1,6 +1,6 @@
 {
   "name": "firecrawl-pdf-inspector",
-  "version": "0.4.2",
+  "version": "0.4.3",
   "description": "Fast PDF classification and text extraction. Detect text-based vs scanned PDFs, extract text by region with quality checks. Native Rust performance via napi-rs.",
   "main": "index.js",
   "types": "index.d.ts",