feat: add CLI commands for account management and email fetching

[frgfm]

This PR:

• adds a CLI with commands to manage email accounts and fetch messages

(base) ➜  relay git:(frgfm/setup) relay --help

 Usage: relay [OPTIONS] COMMAND [ARGS]...

 Relay CLI - Manage your emails efficiently.


╭─ Options ──────────────────────────────────────────────────────────────────────────────────╮
│ --install-completion          Install completion for the current shell.                    │
│ --show-completion             Show completion for the current shell, to copy it or         │
│                               customize the installation.                                  │
│ --help                        Show this message and exit.                                  │
╰────────────────────────────────────────────────────────────────────────────────────────────╯
╭─ Commands ─────────────────────────────────────────────────────────────────────────────────╮
│ version    Show version information.                                                       │
│ account    Account management commands                                                     │
│ messages   Email message commands                                                          │
╰──────────────────────────────────────────────────────────────────────────────────────────

• add CI
• add docs
• add test suite

complete REL-186
complete REL-180

[linear]

INV-180 Docs

• Make neutral colors

[codecov]

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[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	pytest@​8.4.1
	pre-commit@​4.2.0
	ruff@​0.12.2
	rich@​14.0.0
	beautifulsoup4@​4.13.4
	html2text@​2025.4.15
	typer@​0.16.0
	uv-build@​0.7.18
	cryptography@​45.0.5
	pydantic@​2.11.7
	ty@​0.0.1a14
	pytest-cov@​6.2.1
	pytest-pretty@​1.3.0
	pytest-mock@​3.14.1
	questionary@​2.1.0
	email-validator@​2.2.0

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