feat: filter Wishlist from --my-tasks; document the mode (#71)

Tasks in the "Wishlist" bucket version are now excluded from the list
and summary entirely (no due date, noise backlog); exact case match,
tasks without a version are unaffected. Document --my-tasks in README
and the user guide (sorting, summary metrics, OSC 8 links, stream
separation); all examples use synthetic data. Declare ruff
known-first-party in pyproject so the lint result is CWD-independent.

tests/test_mailer.py

@@ -2,6 +2,7 @@ import smtplib
 from unittest import mock
 
 import pytest
+
 from redmine_reporter.client import RedmineAPIError
 from redmine_reporter.config import EmailConfig, SmtpConfig
 from redmine_reporter.mailer import build_message, send_report