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>

frontend/src/services/apiV2.ts

@@ -25,7 +25,6 @@ import type {
   SystemStats,
   UserWithStats,
   TopUser,
-  AuditLog,
   AuditLogListResponse,
   UserActivitySummary,
   ProcessingOptions,
@@ -55,7 +54,7 @@ class ApiClientV2 {
   private token: string | null = null
   private userInfo: UserInfo | null = null
   private tokenExpiresAt: number | null = null
-  private refreshTimer: NodeJS.Timeout | null = null
+  private refreshTimer: ReturnType<typeof setTimeout> | null = null
   private isRefreshing: boolean = false
   private refreshFailed: boolean = false