feat(ai): add ADR-036 unified OCR architecture and frontend test coverage

- Add ADR-036 unified OCR architecture (typhoon-ocr via Ollama)
- Extend AI execution profiles for OCR sandbox configuration
- Add comprehensive frontend test coverage (components, hooks, services)
- Add backend test coverage for document-numbering services
- Update OCR sidecar with typhoon-ocr integration
- Add AI policy service and execution profile management
- Update AGENTS.md and architecture documentation

backend/src/modules/ai/entities/ai-execution-profile.entity.ts

@@ -1,6 +1,7 @@
 // File: backend/src/modules/ai/entities/ai-execution-profile.entity.ts
 // Change Log:
 // - 2026-06-11: Initial creation of AiExecutionProfile entity for AI execution profiles
+// - 2026-06-13: ADR-036 — เพิ่ม canonicalModel และรองรับ nullable OCR params
 
 import {
   Column,
@@ -19,17 +20,20 @@ export class AiExecutionProfile {
   @Column({ name: 'profile_name', unique: true, length: 50 })
   profileName!: string;
 
+  @Column({ name: 'canonical_model', length: 20, default: 'np-dms-ai' })
+  canonicalModel!: 'np-dms-ai' | 'np-dms-ocr';
+
   @Column({ type: 'decimal', precision: 4, scale: 3 })
   temperature!: number;
 
   @Column({ name: 'top_p', type: 'decimal', precision: 4, scale: 3 })
   topP!: number;
 
-  @Column({ name: 'max_tokens', type: 'int' })
-  maxTokens!: number;
+  @Column({ name: 'max_tokens', type: 'int', nullable: true })
+  maxTokens!: number | null;
 
-  @Column({ name: 'num_ctx', type: 'int' })
-  numCtx!: number;
+  @Column({ name: 'num_ctx', type: 'int', nullable: true })
+  numCtx!: number | null;
 
   @Column({ name: 'repeat_penalty', type: 'decimal', precision: 5, scale: 3 })
   repeatPenalty!: number;

backend/src/modules/ai/entities/ai-sandbox-profile.entity.ts

@@ -0,0 +1,51 @@
+// File: backend/src/modules/ai/entities/ai-sandbox-profile.entity.ts
+// Change Log:
+// - 2026-06-13: ADR-036 — เพิ่ม sandbox draft profile entity สำหรับ AI parameter tuning
+
+import {
+  Column,
+  CreateDateColumn,
+  Entity,
+  PrimaryGeneratedColumn,
+  UpdateDateColumn,
+} from 'typeorm';
+
+/** Entity สำหรับเก็บ draft parameters ที่ admin ทดลองก่อน Apply to Production */
+@Entity('ai_sandbox_profiles')
+export class AiSandboxProfile {
+  @PrimaryGeneratedColumn()
+  id!: number;
+
+  @Column({ name: 'profile_name', unique: true, length: 50 })
+  profileName!: string;
+
+  @Column({ name: 'canonical_model', length: 20, default: 'np-dms-ai' })
+  canonicalModel!: 'np-dms-ai' | 'np-dms-ocr';
+
+  @Column({ type: 'decimal', precision: 4, scale: 3 })
+  temperature!: number;
+
+  @Column({ name: 'top_p', type: 'decimal', precision: 4, scale: 3 })
+  topP!: number;
+
+  @Column({ name: 'max_tokens', type: 'int', nullable: true })
+  maxTokens!: number | null;
+
+  @Column({ name: 'num_ctx', type: 'int', nullable: true })
+  numCtx!: number | null;
+
+  @Column({ name: 'repeat_penalty', type: 'decimal', precision: 5, scale: 3 })
+  repeatPenalty!: number;
+
+  @Column({ name: 'keep_alive_seconds', type: 'int' })
+  keepAliveSeconds!: number;
+
+  @Column({ name: 'updated_by', type: 'int', nullable: true })
+  updatedBy?: number | null;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt!: Date;
+
+  @UpdateDateColumn({ name: 'updated_at' })
+  updatedAt!: Date;
+}