Rename the CHANGELOG's [Unreleased] heading to [1.10.0] - 2026-09-19, open
a fresh empty [Unreleased] above it, add the compare links, and bump
_version.py (setup.py reads it, so that is the only place the number lives).

Minor, not patch: this release adds features rather than only fixing things.
allowed_commands limits a profile to named commands (with ai.example.ini as
a starting point for AI assistants), elm COMMAND --info describes a command
without credentials or an API call, misplaced flags now say which side of
the command name they belong on, and tools/elm-ask is new. Nothing existing
changes behaviour: a profile with no allowed_commands runs every command as
before.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>