feat: enable document orientation detection for scanned PDFs

- Enable PP-StructureV3's use_doc_orientation_classify feature
- Detect rotation angle from doc_preprocessor_res.angle
- Swap page dimensions (width <-> height) for 90°/270° rotations
- Output PDF now correctly displays landscape-scanned content

Also includes:
- Archive completed openspec proposals
- Add simplify-frontend-ocr-config proposal (pending)
- Code cleanup and frontend simplification

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

openspec/changes/archive/2025-12-11-use-cellboxes-for-table-rendering/tasks.md

@@ -0,0 +1,48 @@
+## 1. Core Algorithm Implementation
+
+### 1.1 Grid Inference Module
+- [x] 1.1.1 Create `CellBoxGridInferrer` class in `pdf_table_renderer.py`
+- [x] 1.1.2 Implement `cluster_values()` for Y/X coordinate clustering
+- [x] 1.1.3 Implement `infer_grid_from_cellboxes()` main method
+- [x] 1.1.4 Add row_heights and col_widths calculation
+
+### 1.2 Content Mapping
+- [x] 1.2.1 Implement `extract_cell_contents()` from HTML
+- [x] 1.2.2 Implement `map_content_to_grid()` for row-by-row assignment
+- [x] 1.2.3 Handle content count mismatch (more/fewer cells)
+
+## 2. PDF Generator Integration
+
+### 2.1 New Rendering Path
+- [x] 2.1.1 Add `render_from_cellboxes_grid()` method to TableRenderer
+- [x] 2.1.2 Integrate into `draw_table_region()` with cellboxes-first check
+- [x] 2.1.3 Maintain fallback to existing HTML-based rendering
+
+### 2.2 Cell Rendering
+- [x] 2.2.1 Draw cell borders using cell_boxes coordinates
+- [x] 2.2.2 Render text content with proper alignment and padding
+- [x] 2.2.3 Handle multi-line text within cells
+
+## 3. Configuration
+
+### 3.1 Settings
+- [x] 3.1.1 Add `table_rendering_prefer_cellboxes: bool = True`
+- [x] 3.1.2 Add `table_cellboxes_row_threshold: float = 15.0`
+- [x] 3.1.3 Add `table_cellboxes_col_threshold: float = 15.0`
+
+## 4. Testing
+
+### 4.1 Unit Tests
+- [x] 4.1.1 Test grid inference with various cell_box configurations
+- [x] 4.1.2 Test content mapping edge cases
+- [x] 4.1.3 Test coordinate clustering accuracy
+
+### 4.2 Integration Tests
+- [ ] 4.2.1 Test with `scan.pdf` Table 7 (the problematic case)
+- [ ] 4.2.2 Verify no regression on existing table tests
+- [ ] 4.2.3 Visual comparison of output PDFs
+
+## 5. Documentation
+
+- [x] 5.1 Update inline code comments
+- [x] 5.2 Update spec with new table rendering requirement