Update VOICEVOX character list and docs (#19)

東北キャラクター追加とデフォルト変更 (#13)

refactor: remove unused methods identified by vulture (#6)

feat: Enhance audio generation progress visibility

refactor: Update timeout values and remove session recovery steps

feat: Update browser state restoration for Japanese UI

feat: Add Japanese UI text mapping for document and podcast modes

feat: Add browser state persistence for settings changes

fix: Improve URL extraction handling in test mode

fix: Handle empty URL extraction in test mode

fix: Resolve E2E test failures by updating textarea selectors

Revert "feat: Add browser state persistence for podcast script and terms agreement"

feat: Add browser state persistence for podcast script and terms agreement

fix: Fix E2E test failures and improve session initialization

fix: Fix lint issues in test files

feat: Implement browser state restoration using localStorage

refactor: Optimize timeout values for improved test performance

style: Apply comprehensive ruff formatting across entire codebase

feat: Migrate from isort, black, flake8 to ruff for unified linting and formatting

refactor: Update file input handling to prevent duplicate triggers and restrict to single file uploads

refactor: Simplify session cleanup method call in VOICEVOX sharing steps

feat: Enhance audio generation progress display with comprehensive tracking

refactor: Update UserSession import path and clean up related code

Add audio recovery feature and enhance audio state management

refactor: Update file upload and URL extraction tabs for improved clarity and functionality

refactor: Clean up code formatting and improve readability across multiple files

refactor: Remove redundant UI layout verification steps from text management tests

feat: Enhance URL extraction and text management features

Add URL extraction feature and related tests

Refactor session management by removing SessionManager and integrating functionality into UserSession

Implement global VOICEVOX Core manager for shared audio generation across users

Fix mypy typing errors

Reduce timeout values for UI element loading in common_steps.py

Improve application loading checks in common_steps.py

Refactor E2E test environment: consolidate setup and teardown logic into TestEnvironment class and update related fixtures

Refactor E2E test setup: consolidate environment setup into conftest.py and remove redundant steps from common_steps.py

Enhance CI workflow: add environment verification step and improve Python executable handling in E2E tests

Refactor unit tests for SessionManager and TextProcessor classes