refactor: enable TypeScript strict mode and fix memory leak

- tsconfig.json: strict: true 활성화 (noImplicitAny, strictNullChecks를 대체)
- main.ts: definite assignment assertions (!) 추가 — Obsidian Plugin은 onload()에서 초기화
- settings-tab.ts: strictFunctionTypes 호환을 위해 onChange 타입 캐스트
- settings-tab.ts: hide() 오버라이드로 debounceTimer 정리 (메모리 누수 수정)

Closes #38

src/main.ts

@@ -21,23 +21,23 @@ import { AutoNoteImporterSettingTab } from './ui';
  * Main plugin class for Auto Note Importer.
  */
 export default class AutoNoteImporterPlugin extends Plugin {
-  settings: AutoNoteImporterSettings;
+  settings!: AutoNoteImporterSettings;
   private intervalId: number | null = null;
-  private settingTab: AutoNoteImporterSettingTab;
+  private settingTab!: AutoNoteImporterSettingTab;
 
-  // Services
-  private airtableClient: AirtableClient;
-  private fieldCache: FieldCache;
-  private rateLimiter: RateLimiter;
+  // Services (initialized in onload → initializeServices)
+  private airtableClient!: AirtableClient;
+  private fieldCache!: FieldCache;
+  private rateLimiter!: RateLimiter;
 
   // Core
-  private syncQueue: SyncQueue;
-  private conflictResolver: ConflictResolver;
-  private syncOrchestrator: SyncOrchestrator;
+  private syncQueue!: SyncQueue;
+  private conflictResolver!: ConflictResolver;
+  private syncOrchestrator!: SyncOrchestrator;
 
   // File Operations
-  private frontmatterParser: FrontmatterParser;
-  private fileWatcher: FileWatcher;
+  private frontmatterParser!: FrontmatterParser;
+  private fileWatcher!: FileWatcher;
 
   async onload() {
     await this.loadSettings();

src/ui/settings-tab.ts

@@ -53,6 +53,13 @@ export class AutoNoteImporterSettingTab extends PluginSettingTab {
       });
   }
 
+  hide(): void {
+    if (this.debounceTimer) {
+      clearTimeout(this.debounceTimer);
+      this.debounceTimer = null;
+    }
+  }
+
   display(): void {
     const { containerEl } = this;
     containerEl.empty();
@@ -309,8 +316,8 @@ export class AutoNoteImporterSettingTab extends PluginSettingTab {
           .addOption('synced-folder', 'Inside synced folder')
           .addOption('custom', 'Custom path')
           .setValue(this.plugin.settings.basesFileLocation)
-          .onChange(async (value: BasesFileLocation) => {
-            this.plugin.settings.basesFileLocation = value;
+          .onChange(async (value) => {
+            this.plugin.settings.basesFileLocation = value as BasesFileLocation;
             await this.plugin.saveSettings();
             this.debounceDisplay();
           }));
@@ -366,8 +373,8 @@ export class AutoNoteImporterSettingTab extends PluginSettingTab {
           .addOption('obsidian-wins', 'Obsidian wins (overwrite Airtable)')
           .addOption('airtable-wins', 'Airtable wins (overwrite Obsidian)')
           .setValue(this.plugin.settings.conflictResolution)
-          .onChange(async (value: ConflictResolutionMode) => {
-            this.plugin.settings.conflictResolution = value;
+          .onChange(async (value) => {
+            this.plugin.settings.conflictResolution = value as ConflictResolutionMode;
             await this.plugin.saveSettings();
           }));
 

tsconfig.json

@@ -6,11 +6,10 @@
     "module": "ESNext",
     "target": "ES6",
     "allowJs": true,
-    "noImplicitAny": true,
+    "strict": true,
     "moduleResolution": "node",
     "importHelpers": true,
     "isolatedModules": true,
-    "strictNullChecks": true,
     "lib": [
       "DOM",
       "ES5",