fix: coerce is_strictly_forces_https return value to bool

[steps-re]

Fixes #176.

Problem

is_strictly_forces_https could return None instead of True/False, which caused the "Strictly Forces HTTPS" JSON field to be null for some domains.

The root cause was in the down_or_redirects inner helper:

# before
def down_or_redirects(endpoint):
    return not endpoint.live or endpoint.redirect_immediately_to_https

redirect_immediately_to_https defaults to None in models.py (line 58). When endpoint.live is True, Python evaluates False or None as None. That None then propagates through the and chain on line 1280, so the final return value is None rather than a bool.

Fix

Wrap the attribute in bool() in the helper, and apply the same treatment to https_somewhere:

def down_or_redirects(endpoint):
    return (not endpoint.live) or bool(endpoint.redirect_immediately_to_https)

https_somewhere = bool(https.live or httpswww.live)

Both bool(None) → False and bool(True) → True, so the semantics are unchanged for any non-None value.

Tests

Adds TestStrictlyForcesHttps with three cases:

• All endpoints at default (None) state → returns False, not None
• HTTPS live, HTTP live with redirect_immediately_to_https=None → returns False, not None
• HTTPS live, HTTP endpoints both redirecting to HTTPS → returns True

[jsf9k]

Thank you for the contribution @steps-re!

[dav3r]

LGTM - thanks @steps-re for your contribution! 👍