# Implementation Plan: Inactive Sessions Purging, Form Data Persistence, and Centralized Snackbars

**Branch**: `009-inactive-sessions-purging` | **Date**: четверг, 16 октября 2025 г. | **Spec**: D:\\Coding\\unisono\\specs\\009-inactive-sessions-purging\\spec.md
**Input**: Feature specification from `/specs/009-inactive-sessions-purging/spec.md`

**Note**: This template is filled in by the `/speckit.plan` command. See `.specify/templates/commands/plan.md` for the execution workflow.

## Summary

This feature implements automatic purging of inactive user sessions, real-time persistence of unsubmitted form input values using WebSockets, and consistent display of snackbar notifications in the top right corner of the UI.

## Technical Context

**Language/Version**: TypeScript 5.x, Node.js (LTS)
**Primary Dependencies**: React, Material-UI / MUI, WebSocket library
**Storage**: Ephemeral server-side session storage (in-memory/session store)
**Testing**: Jest, React Testing Library
**Target Platform**: Web (browser for frontend, Node.js server for backend)
**Project Type**: Web application (frontend + backend)
**Performance Goals**: Maintain performance and stability for up to 100 concurrent active user sessions
**Constraints**: Session inactivity timeout configurable via environment variable
**Scale/Scope**: Up to 100 concurrent active user sessions

## Constitution Check

*GATE: Must pass before Phase 0 research. Re-check after Phase 1 design.*

### I. Defined Technology Stack: PASS
- Backend: Node.js - PASS
- Frontend: React - PASS
- UI Framework: Material Design 3 (Material-UI / MUI) - PASS
- Containerization: Docker - PASS

### II. UI/UX Consistency: PASS
- All user interfaces MUST adhere to Material Design 3 principles and components. - PASS

### III. Container-First Development: PASS
- All application services and development environments MUST run within Docker containers. - PASS

### IV. Test-Driven Development (TDD): PASS
- New features and bug fixes MUST follow a Test-Driven Development approach. - PASS

### V. API-First Design: PASS
- The backend and frontend are decoupled and communicate via a well-defined API contract. - PASS


## Project Structure

### Documentation (this feature)

```
specs/[###-feature]/
├── plan.md              # This file (/speckit.plan command output)
├── research.md          # Phase 0 output (/speckit.plan command)
├── data-model.md        # Phase 1 output (/speckit.plan command)
├── quickstart.md        # Phase 1 output (/speckit.plan command)
├── contracts/           # Phase 1 output (/speckit.plan command)
└── tasks.md             # Phase 2 output (/speckit.tasks command - NOT created by /speckit.plan)
```

### Source Code (repository root)
<!--
  ACTION REQUIRED: Replace the placeholder tree below with the concrete layout
  for this feature. Delete unused options and expand the chosen structure with
  real paths (e.g., apps/admin, packages/something). The delivered plan must
  not include Option labels.
-->

```
# [REMOVE IF UNUSED] Option 1: Single project (DEFAULT)
src/
├── models/
├── services/
├── cli/
└── lib/

tests/
├── contract/
├── integration/
├── unit/

# [REMOVE IF UNUSED] Option 2: Web application (when "frontend" + "backend" detected)
backend/
├── src/
│   ├── models/
│   ├── services/
│   └── api/
└── tests/

frontend/
├── src/
│   ├── components/
│   ├── pages/
│   └── services/
└── tests/

# [REMOVE IF UNUSED] Option 3: Mobile + API (when "iOS/Android" detected)
api/
└── [same as backend above]

ios/ or android/
└── [platform-specific structure: feature modules, UI flows, platform tests]
```

**Structure Decision**: [Document the selected structure and reference the real
directories captured above]

## Complexity Tracking

*Fill ONLY if Constitution Check has violations that must be justified*

| Violation | Why Needed | Simpler Alternative Rejected Because |
|-----------|------------|-------------------------------------|
| [e.g., 4th project] | [current need] | [why 3 projects insufficient] |
| [e.g., Repository pattern] | [specific problem] | [why direct DB access insufficient] |