feat: add commune tool for email and SMS

[shanjairaj7]

Summary

This PR adds a Commune tool to AgentStack, giving agents a programmable email and SMS layer built specifically for AI workflows.

What is Commune?

Commune is not SMTP, not a human webmail client — it's an API-first communication platform designed for agents. Each project gets a dedicated email address and phone-capable inbox that the agent reads and writes programmatically. Think of it as the agent's own mailbox and phone line, accessible via a clean Python SDK.

• PyPI: commune-mail (MIT license)
• API docs: https://docs.commune.email

Tools added (agentstack/_tools/commune/)

Tool	What it does
send_email(to, subject, body)	Sends an email from the agent's Commune address and returns a confirmation with the message ID
read_inbox(limit=10)	Fetches recent emails from the inbox and returns a numbered, human-readable list with sender, subject, timestamp, and body preview
send_sms(to, body)	Sends an SMS to an E.164 phone number, with client-side format validation before the API call

What this enables

• Agents that send transactional emails or status reports (e.g. "run finished, here are the results")
• Agents that poll their inbox and respond to incoming instructions or approvals
• Agents that fire SMS alerts for time-sensitive events (on-call notifications, OTP codes, confirmations)

Quick example

from agentstack._tools.commune import send_email, read_inbox, send_sms

# Agent sends a report
send_email(
    to="team@example.com",
    subject="Nightly analysis complete",
    body="The pipeline finished at 03:14 UTC. 0 errors. Full report attached in the dashboard."
)

# Agent checks for replies before proceeding
messages = read_inbox(limit=5)
print(messages)

# Agent fires an SMS alert
send_sms(to="+15551234567", body="Pipeline alert: anomaly detected in sensor data. Check dashboard.")

Checklist

• __init__.py with 3 tool functions, each with full docstrings
• config.json with name, url, category, env, dependencies, tools, cta
• E.164 validation on send_sms before API call
• Follows same structure as exa and agentmail tools