chore: archive upgrade-ppstructure-models proposal

Archived as 2025-11-27-upgrade-ppstructure-models
Spec updated: ocr-processing (added PP-StructureV3 Configuration)

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

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

openspec/specs/ocr-processing/spec.md

@@ -186,3 +186,12 @@ The frontend SHALL provide a simple, user-friendly interface for selecting layou
 - **THEN** layout model selection SHALL be shown ONLY when OCR track is selected or auto-detected
 - **AND** SHALL be hidden for Direct track (which does not use PP-StructureV3)
 
+### Requirement: Model Cache Cleanup
+
+The system SHALL provide documentation for cleaning up unused model caches to optimize storage space.
+
+#### Scenario: User wants to free disk space after model upgrade
+- **WHEN** the user has upgraded from older models (PP-DocLayout-S, SLANet) to newer models
+- **THEN** the documentation SHALL explain how to delete unused cached models from `~/.paddlex/official_models/`
+- **AND** list which model directories can be safely removed
+