chore: backup before code cleanup

Backup commit before executing remove-unused-code proposal.
This includes all pending changes and new features.

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

openspec/changes/archive/2025-12-10-add-ocr-processing-presets/proposal.md

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+# Proposal: Add OCR Processing Presets and Parameter Configuration
+
+## Summary
+
+Add frontend UI for configuring PP-Structure OCR processing parameters with document-type presets and advanced parameter tuning. This addresses the root cause of table over-detection by allowing users to select appropriate processing modes for their document types.
+
+## Problem Statement
+
+Currently, PP-Structure's table parsing is too aggressive for many document types:
+1. **Layout detection** misclassifies structured text (e.g., datasheet right columns) as tables
+2. **Table cell parsing** over-segments these regions, causing "cell explosion"
+3. **Post-processing patches** (cell validation, gap filling, table rebuilder) try to fix symptoms but don't address root cause
+4. **No user control** - all settings are hardcoded in backend config.py
+
+## Proposed Solution
+
+### 1. Document Type Presets (Simple Mode)
+
+Provide predefined configurations for common document types:
+
+| Preset | Description | Table Parsing | Layout Threshold | Use Case |
+|--------|-------------|---------------|------------------|----------|
+| `text_heavy` | Documents with mostly paragraphs | disabled | 0.7 | Reports, articles, manuals |
+| `datasheet` | Technical datasheets with tables/specs | conservative | 0.65 | Product specs, TDS |
+| `table_heavy` | Documents with many tables | full | 0.5 | Financial reports, spreadsheets |
+| `form` | Forms with fields | conservative | 0.6 | Applications, surveys |
+| `mixed` | Mixed content documents | classification_only | 0.55 | General documents |
+| `custom` | User-defined settings | user-defined | user-defined | Advanced users |
+
+### 2. Advanced Parameter Panel (Expert Mode)
+
+Expose all PP-Structure parameters for fine-tuning:
+
+**Table Processing:**
+- `table_parsing_mode`: full / conservative / classification_only / disabled
+- `table_layout_threshold`: 0.0 - 1.0 (higher = stricter table detection)
+- `enable_wired_table`: true / false
+- `enable_wireless_table`: true / false
+- `wired_table_model`: model selection
+- `wireless_table_model`: model selection
+
+**Layout Detection:**
+- `layout_detection_model`: model selection
+- `layout_threshold`: 0.0 - 1.0
+- `layout_nms_threshold`: 0.0 - 1.0
+- `layout_merge_mode`: large / small / union
+
+**Preprocessing:**
+- `use_doc_orientation_classify`: true / false
+- `use_doc_unwarping`: true / false
+- `use_textline_orientation`: true / false
+
+**Other Recognition:**
+- `enable_chart_recognition`: true / false
+- `enable_formula_recognition`: true / false
+- `enable_seal_recognition`: true / false
+
+### 3. API Endpoint
+
+Add endpoint to accept processing configuration:
+
+```
+POST /api/v2/tasks
+{
+  "file": ...,
+  "processing_track": "ocr",
+  "ocr_preset": "datasheet",  // OR
+  "ocr_config": {
+    "table_parsing_mode": "conservative",
+    "table_layout_threshold": 0.65,
+    ...
+  }
+}
+```
+
+### 4. Frontend UI Components
+
+1. **Preset Selector**: Dropdown with document type icons and descriptions
+2. **Advanced Toggle**: Expand/collapse for parameter panel
+3. **Parameter Groups**: Collapsible sections for table/layout/preprocessing
+4. **Real-time Preview**: Show expected behavior based on settings
+
+## Benefits
+
+1. **Root cause fix**: Address table over-detection at the source
+2. **User empowerment**: Users can optimize for their specific documents
+3. **No patches needed**: Clean PP-Structure output without post-processing hacks
+4. **Iterative improvement**: Users can fine-tune and share working configurations
+
+## Scope
+
+- Backend: API endpoint, preset definitions, parameter validation
+- Frontend: UI components for preset selection and parameter tuning
+- No changes to PP-Structure core - only configuration
+
+## Success Criteria
+
+1. Users can select appropriate preset for document type
+2. OCR output matches document reality without post-processing patches
+3. Advanced users can fine-tune all PP-Structure parameters
+4. Configuration can be saved and reused
+
+## Risks & Mitigations
+
+| Risk | Mitigation |
+|------|------------|
+| Users overwhelmed by parameters | Default to presets, hide advanced panel |
+| Wrong preset selection | Provide visual examples for each preset |
+| Breaking changes | Keep backward compatibility with defaults |
+
+## Timeline
+
+Phase 1: Backend API and presets (2-3 days)
+Phase 2: Frontend preset selector (1-2 days)
+Phase 3: Advanced parameter panel (2-3 days)
+Phase 4: Documentation and testing (1 day)