diff --git a/docs/REFACTOR-AND-TEST.md b/docs/REFACTOR-AND-TEST.md
index 43fdb56..5a0e43f 100644
--- a/docs/REFACTOR-AND-TEST.md
+++ b/docs/REFACTOR-AND-TEST.md
@@ -1,5 +1,8 @@
 # Vitest + Clean Architecture Refactoring
 
+> **Статус: выполнено / архив**  
+> План закрыт, дальше не ведём и не обновляем. Исторический снимок задачи.
+
 ## Цель
 
 Установить Vitest, переделать архитектуру ближе к чистой (порты/адаптеры),
diff --git a/eslint.config.mjs b/eslint.config.mjs
index 464b248..34fdad0 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -37,6 +37,25 @@ export default defineConfig(
 					caughtErrorsIgnorePattern: "^_",
 				},
 			],
+			"@typescript-eslint/parameter-properties": [
+				"error",
+				{
+					prefer: "class-property",
+					allow: [],
+				},
+			],
+			"@typescript-eslint/naming-convention": [
+				"error",
+				{
+					selector: "classProperty",
+					modifiers: ["private"],
+					format: null,
+					custom: {
+						regex: "^.*$",
+						match: false,
+					},
+				},
+			],
 		},
 	},
 	{
diff --git a/src/storage/FsTaskRepository.test.ts b/src/storage/FsTaskRepository.test.ts
index de1773c..5d2b018 100644
--- a/src/storage/FsTaskRepository.test.ts
+++ b/src/storage/FsTaskRepository.test.ts
@@ -4,11 +4,18 @@ import { beforeEach, describe, expect, it } from "vitest";
 import { InMemoryFileSystem } from "../../tests/helpers/InMemoryFileSystem";
 import { FsTaskRepository } from "./FsTaskRepository";
 
+const UUID_RE =
+	/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
+
 describe("FsTaskRepository", () => {
 	let fs: InMemoryFileSystem;
 	let repo: ITaskRepository;
+	let clockStep: number;
 
 	const folder = "/tasks";
+	const t0 = "2026-01-01T00:00:00.000Z";
+	const t1 = "2026-01-01T00:00:01.000Z";
+	const t2 = "2026-01-01T00:00:02.000Z";
 
 	const sampleTask = {
 		title: "Fix login bug",
@@ -21,35 +28,41 @@ describe("FsTaskRepository", () => {
 
 	beforeEach(() => {
 		fs = new InMemoryFileSystem();
-		repo = new FsTaskRepository(fs, ".task.md");
+		clockStep = 0;
+		const timestamps = [t0, t1, t2];
+		repo = new FsTaskRepository(fs, ".task.md", () => {
+			const value = timestamps[clockStep] ?? t2;
+			clockStep += 1;
+			return value;
+		});
 	});
 
 	it("creates a task and writes it as a .task.md file", async () => {
 		const task = await repo.create(folder, sampleTask);
 
-		expect(task.id).toBeTruthy();
+		expect(task.id).toMatch(UUID_RE);
 		expect(task.title).toBe("Fix login bug");
-		expect(task.created).toBeTruthy();
-		expect(task.updated).toBe(task.created);
+		expect(task.created).toBe(t0);
+		expect(task.updated).toBe(t0);
 
 		const files = await fs.readdir(folder);
-		expect(files).toHaveLength(1);
-		expect(files[0]).toMatch(/\.task\.md$/);
+		expect(files).toEqual(["fix-login-bug.task.md"]);
 
-		const content = await fs.readFile(`${folder}/${files[0]}`);
+		const content = await fs.readFile(`${folder}/fix-login-bug.task.md`);
 		expect(content).toContain("Fix login bug");
 		expect(content).toContain("status: todo");
 	});
 
 	it("list returns created tasks sorted by updated desc", async () => {
 		await repo.create(folder, { ...sampleTask, title: "A" });
-		await delay(10);
 		await repo.create(folder, { ...sampleTask, title: "B" });
 
 		const tasks = await repo.list(folder);
 		expect(tasks).toHaveLength(2);
 		expect(tasks[0].title).toBe("B");
+		expect(tasks[0].updated).toBe(t1);
 		expect(tasks[1].title).toBe("A");
+		expect(tasks[1].updated).toBe(t0);
 	});
 
 	it("getById returns the correct task", async () => {
@@ -63,19 +76,50 @@ describe("FsTaskRepository", () => {
 		expect(found).toBeUndefined();
 	});
 
-	it("update modifies the file and updates timestamp", async () => {
+	it("update modifies fields and bumps updated timestamp", async () => {
 		const task = await repo.create(folder, sampleTask);
-		await delay(5);
-		const updated: Task = { ...task, title: "Fixed!", status: "done" };
+		const updated: Task = { ...task, status: "done" };
 
 		await repo.update(folder, updated);
 		const found = await repo.getById(folder, task.id);
 
-		expect(found!.title).toBe("Fixed!");
 		expect(found!.status).toBe("done");
-		expect(new Date(found!.updated).getTime()).toBeGreaterThan(
-			new Date(task.updated).getTime(),
-		);
+		expect(found!.title).toBe(task.title);
+		expect(found!.updated).toBe(t1);
+		expect(found!.created).toBe(t0);
+	});
+
+	it("update renames file when title changes", async () => {
+		const task = await repo.create(folder, sampleTask);
+		expect(await fs.readdir(folder)).toEqual(["fix-login-bug.task.md"]);
+
+		await repo.update(folder, { ...task, title: "Fixed!" });
+
+		const files = await fs.readdir(folder);
+		expect(files).toEqual(["fixed.task.md"]);
+		const found = await repo.getById(folder, task.id);
+		expect(found!.title).toBe("Fixed!");
+		expect(found!.updated).toBe(t1);
+	});
+
+	it("update of unknown id writes a new file", async () => {
+		const orphan: Task = {
+			...sampleTask,
+			id: "orphan-id",
+			title: "Orphan",
+			created: t0,
+			updated: t0,
+		};
+
+		await repo.update(folder, orphan);
+
+		const found = await repo.getById(folder, "orphan-id");
+		expect(found).toMatchObject({
+			id: "orphan-id",
+			title: "Orphan",
+			updated: t0,
+		});
+		expect(await fs.readdir(folder)).toEqual(["orphan.task.md"]);
 	});
 
 	it("delete removes the task file", async () => {
@@ -84,6 +128,7 @@ describe("FsTaskRepository", () => {
 
 		const tasks = await repo.list(folder);
 		expect(tasks).toHaveLength(0);
+		expect(await fs.readdir(folder)).toEqual([]);
 	});
 
 	it("delete is a no-op for unknown id", async () => {
@@ -96,8 +141,8 @@ describe("FsTaskRepository", () => {
 	});
 
 	it("filters files by extension", async () => {
-		fs.writeFile(`${folder}/notes.txt`, "hello");
-		fs.writeFile(`${folder}/chore.md`, "---\nid: x\n---\n");
+		await fs.writeFile(`${folder}/notes.txt`, "hello");
+		await fs.writeFile(`${folder}/chore.md`, "---\nid: x\n---\n");
 
 		await repo.create(folder, sampleTask);
 
@@ -105,15 +150,41 @@ describe("FsTaskRepository", () => {
 		expect(tasks).toHaveLength(1);
 	});
 
-	it("skips unparseable .task.md files silently", async () => {
-		fs.writeFile(`${folder}/corrupt.task.md`, "not valid frontmatter");
+	it("list returns empty when only non-matching extensions exist", async () => {
+		await fs.writeFile(`${folder}/notes.txt`, "hello");
+		await fs.writeFile(`${folder}/chore.md`, "---\nid: x\n---\n");
+
+		const tasks = await repo.list(folder);
+		expect(tasks).toEqual([]);
+	});
+
+	it("skips files without id", async () => {
+		await fs.writeFile(`${folder}/no-id.task.md`, "not valid frontmatter");
+		await fs.writeFile(
+			`${folder}/empty-id.task.md`,
+			"---\ntitle: No Id\n---\n",
+		);
 
 		await repo.create(folder, sampleTask);
 		const tasks = await repo.list(folder);
 		expect(tasks).toHaveLength(1);
+		expect(tasks[0].title).toBe("Fix login bug");
+	});
+
+	it("create with same title overwrites the previous file", async () => {
+		const first = await repo.create(folder, sampleTask);
+		const second = await repo.create(folder, {
+			...sampleTask,
+			description: "second",
+		});
+
+		const files = await fs.readdir(folder);
+		expect(files).toEqual(["fix-login-bug.task.md"]);
+
+		const tasks = await repo.list(folder);
+		expect(tasks).toHaveLength(1);
+		expect(tasks[0].id).toBe(second.id);
+		expect(tasks[0].id).not.toBe(first.id);
+		expect(tasks[0].description).toBe("second");
 	});
 });
-
-function delay(ms: number): Promise<void> {
-	return new Promise((r) => setTimeout(r, ms));
-}
diff --git a/src/storage/FsTaskRepository.ts b/src/storage/FsTaskRepository.ts
index 96bbe55..a21ceaa 100644
--- a/src/storage/FsTaskRepository.ts
+++ b/src/storage/FsTaskRepository.ts
@@ -5,27 +5,38 @@ import { generateId } from "@/utils/uuid";
 
 const MAX_SAFE_NAME_LENGTH = 80;
 
+export type NowFn = () => string;
+
 export class FsTaskRepository implements ITaskRepository {
+	#fs: IFileSystem;
+	#fileExtension: string;
+	#now: NowFn;
+
 	constructor(
-		private fs: IFileSystem,
-		private fileExtension: string,
-	) {}
+		fs: IFileSystem,
+		fileExtension: string,
+		now: NowFn = () => new Date().toISOString(),
+	) {
+		this.#fs = fs;
+		this.#fileExtension = fileExtension;
+		this.#now = now;
+	}
 
 	async list(folderPath: string): Promise<Task[]> {
 		let entries: string[];
 		try {
-			entries = await this.fs.readdir(folderPath);
+			entries = await this.#fs.readdir(folderPath);
 		} catch {
 			return [];
 		}
 
-		const files = entries.filter((name) => name.endsWith(this.fileExtension));
+		const files = entries.filter((name) => name.endsWith(this.#fileExtension));
 		const tasks: Task[] = [];
 
 		for (const file of files) {
 			try {
 				const fullPath = this.joinPath(folderPath, file);
-				const content = await this.fs.readFile(fullPath);
+				const content = await this.#fs.readFile(fullPath);
 				const task = parseTaskFile(content);
 				if (!task.id) continue;
 				tasks.push(task);
@@ -48,7 +59,7 @@ export class FsTaskRepository implements ITaskRepository {
 		folderPath: string,
 		task: Omit<Task, "id" | "created" | "updated">,
 	): Promise<Task> {
-		const now = new Date().toISOString();
+		const now = this.#now();
 		const newTask: Task = {
 			...task,
 			id: generateId(),
@@ -56,26 +67,26 @@ export class FsTaskRepository implements ITaskRepository {
 			updated: now,
 		};
 
-		await this.fs.mkdir(folderPath);
+		await this.#fs.mkdir(folderPath);
 		const filePath = this.taskFilePath(folderPath, newTask);
-		await this.fs.writeFile(filePath, serializeTask(newTask));
+		await this.#fs.writeFile(filePath, serializeTask(newTask));
 
 		return newTask;
 	}
 
 	async update(folderPath: string, task: Task): Promise<void> {
 		const existing = await this.getById(folderPath, task.id);
-		const updatedTask = { ...task, updated: new Date().toISOString() };
+		const updatedTask = { ...task, updated: this.#now() };
 		const newPath = this.taskFilePath(folderPath, updatedTask);
 
 		if (existing) {
 			const oldPath = this.taskFilePath(folderPath, existing);
 			if (oldPath !== newPath) {
-				await this.fs.deleteFile(oldPath).catch(() => {});
+				await this.#fs.deleteFile(oldPath).catch(() => {});
 			}
 		}
 
-		await this.fs.writeFile(newPath, serializeTask(updatedTask));
+		await this.#fs.writeFile(newPath, serializeTask(updatedTask));
 	}
 
 	async delete(folderPath: string, id: string): Promise<void> {
@@ -84,7 +95,7 @@ export class FsTaskRepository implements ITaskRepository {
 
 		const filePath = this.taskFilePath(folderPath, task);
 		try {
-			await this.fs.deleteFile(filePath);
+			await this.#fs.deleteFile(filePath);
 		} catch {
 			// already gone
 		}
@@ -97,7 +108,7 @@ export class FsTaskRepository implements ITaskRepository {
 			.replace(/^-|-$/g, "")
 			.slice(0, MAX_SAFE_NAME_LENGTH);
 
-		return this.joinPath(folderPath, `${safeName}${this.fileExtension}`);
+		return this.joinPath(folderPath, `${safeName}${this.#fileExtension}`);
 	}
 
 	private joinPath(...segments: string[]): string {
diff --git a/src/utils/markdown.test.ts b/src/utils/markdown.test.ts
index abfd473..1850e22 100644
--- a/src/utils/markdown.test.ts
+++ b/src/utils/markdown.test.ts
@@ -1,6 +1,8 @@
-import { describe, it, expect } from "vitest";
-import { parseTaskFile, serializeTask } from "./markdown";
 import { Task } from "@/model/task";
+import { describe, expect, it } from "vitest";
+import { parseTaskFile, serializeTask } from "./markdown";
+
+const ISO_RE = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z$/;
 
 const fullTask: Task = {
 	id: "550e8400-e29b-41d4-a716-446655440000",
@@ -51,20 +53,17 @@ describe("markdown", () => {
 		expect(task.priority).toBe("medium");
 		expect(task.tags).toEqual([]);
 		expect(task.assignee).toBe("");
-		expect(task.created).toBeTruthy();
-		expect(task.updated).toBeTruthy();
-	});
-
-	it("serializeTask produces valid frontmatter", () => {
-		const result = serializeTask(fullTask);
-		expect(result).toContain("---");
-		expect(result).toContain("title: Пофиксить баг логина");
-		expect(result).toContain("status: in-progress");
-		expect(result).toContain("Ошибка валидации токена");
+		expect(task.created).toMatch(ISO_RE);
+		expect(task.updated).toMatch(ISO_RE);
 	});
 
 	it("round-trip: serialize → parse produces the same task", () => {
 		const serialized = serializeTask(fullTask);
+		expect(serialized).toContain("---");
+		expect(serialized).toContain("title: Пофиксить баг логина");
+		expect(serialized).toContain("status: in-progress");
+		expect(serialized).toContain("Ошибка валидации токена");
+
 		const parsed = parseTaskFile(serialized);
 		expect(parsed).toEqual(fullTask);
 	});
@@ -78,4 +77,23 @@ describe("markdown", () => {
 		const parsed = parseTaskFile(serialized);
 		expect(parsed.description).toBe(task.description);
 	});
+
+	it("converts Date values from YAML to ISO strings", () => {
+		const created = new Date("2026-07-12T10:00:00.000Z");
+		const updated = new Date("2026-07-12T11:00:00.000Z");
+		const content = [
+			"---",
+			'id: "date-task"',
+			'title: "With dates"',
+			`created: ${created.toISOString()}`,
+			`updated: ${updated.toISOString()}`,
+			"---",
+			"",
+		].join("\n");
+
+		// front-matter/js-yaml may return Date for unquoted ISO-like timestamps
+		const task = parseTaskFile(content);
+		expect(task.created).toBe("2026-07-12T10:00:00.000Z");
+		expect(task.updated).toBe("2026-07-12T11:00:00.000Z");
+	});
 });
diff --git a/src/views/taskTreeProvider.ts b/src/views/taskTreeProvider.ts
index 4ab077e..36a9153 100644
--- a/src/views/taskTreeProvider.ts
+++ b/src/views/taskTreeProvider.ts
@@ -1,6 +1,6 @@
-import * as vscode from "vscode";
 import { Task, TaskStatus } from "@/model/task";
 import { IConfigProvider, ITaskRepository } from "@/ports";
+import * as vscode from "vscode";
 
 const STATUS_ORDER: TaskStatus[] = ["todo", "in-progress", "done", "cancelled"];
 
@@ -12,30 +12,32 @@ const STATUS_ICONS: Record<TaskStatus, vscode.ThemeIcon> = {
 };
 
 class TaskGroupTreeItem extends vscode.TreeItem {
-	constructor(
-		label: string,
-		public readonly tasks: Task[],
-		icon: vscode.ThemeIcon,
-	) {
+	readonly tasks: Task[];
+
+	constructor(label: string, tasks: Task[], icon: vscode.ThemeIcon) {
 		super(label, vscode.TreeItemCollapsibleState.Collapsed);
 		this.iconPath = icon;
+		this.tasks = tasks;
 		this.description = `(${tasks.length})`;
 	}
 }
 
 export class TaskTreeProvider implements vscode.TreeDataProvider<vscode.TreeItem> {
-	private _onDidChangeTreeData = new vscode.EventEmitter<
+	#onDidChangeTreeData = new vscode.EventEmitter<
 		vscode.TreeItem | undefined | null | void
 	>();
-	readonly onDidChangeTreeData = this._onDidChangeTreeData.event;
+	readonly onDidChangeTreeData = this.#onDidChangeTreeData.event;
 
-	constructor(
-		private taskStore: ITaskRepository,
-		private configStore: IConfigProvider,
-	) {}
+	#taskStore: ITaskRepository;
+	#configStore: IConfigProvider;
+
+	constructor(taskStore: ITaskRepository, configStore: IConfigProvider) {
+		this.#taskStore = taskStore;
+		this.#configStore = configStore;
+	}
 
 	refresh(): void {
-		this._onDidChangeTreeData.fire();
+		this.#onDidChangeTreeData.fire();
 	}
 
 	getTreeItem(element: vscode.TreeItem): vscode.TreeItem {
@@ -50,19 +52,23 @@ export class TaskTreeProvider implements vscode.TreeDataProvider<vscode.TreeItem
 	}
 
 	private async getRootChildren(): Promise<vscode.TreeItem[]> {
-		const projectPath = this.configStore.getProjectTaskPath();
+		const projectPath = this.#configStore.getProjectTaskPath();
 		if (!projectPath) {
 			return [new vscode.TreeItem("Open a workspace folder to start")];
 		}
 
-		const tasks = await this.taskStore.list(projectPath);
+		const tasks = await this.#taskStore.list(projectPath);
 
 		return STATUS_ORDER.map((status) => {
 			const groupTasks = tasks.filter((t) => t.status === status);
-			const label = status === "todo" ? "To Do"
-				: status === "in-progress" ? "In Progress"
-				: status === "done" ? "Done"
-				: "Cancelled";
+			const label =
+				status === "todo"
+					? "To Do"
+					: status === "in-progress"
+						? "In Progress"
+						: status === "done"
+							? "Done"
+							: "Cancelled";
 			const item = new TaskGroupTreeItem(
 				label,
 				groupTasks,
diff --git a/tests/helpers/InMemoryFileSystem.ts b/tests/helpers/InMemoryFileSystem.ts
index f6eae98..186fe96 100644
--- a/tests/helpers/InMemoryFileSystem.ts
+++ b/tests/helpers/InMemoryFileSystem.ts
@@ -1,14 +1,14 @@
 import { IFileSystem } from "@/ports";
 
 export class InMemoryFileSystem implements IFileSystem {
-	private files = new Map<string, string>();
+	#files = new Map<string, string>();
 
 	reset(): void {
-		this.files.clear();
+		this.#files.clear();
 	}
 
 	async readFile(path: string): Promise<string> {
-		const content = this.files.get(path);
+		const content = this.#files.get(path);
 		if (content === undefined) {
 			throw new Error(`ENOENT: no such file: ${path}`);
 		}
@@ -16,17 +16,17 @@ export class InMemoryFileSystem implements IFileSystem {
 	}
 
 	async writeFile(path: string, content: string): Promise<void> {
-		this.files.set(path, content);
+		this.#files.set(path, content);
 	}
 
 	async deleteFile(path: string): Promise<void> {
-		this.files.delete(path);
+		this.#files.delete(path);
 	}
 
 	async readdir(path: string): Promise<string[]> {
 		const prefix = path.endsWith("/") || path.endsWith("\\") ? path : path + "/";
 		const seen = new Set<string>();
-		for (const key of this.files.keys()) {
+		for (const key of this.#files.keys()) {
 			if (key.startsWith(prefix)) {
 				const relative = key.slice(prefix.length);
 				const top = relative.split(/[/\\]/)[0];