The second scenario, chosen to be a bridge rather than another HTTP
component: bridges are roughly 40 of the 70 roles here, and validating the
shape on role two is cheaper than discovering it on role forty. It found
two things the first role could not.

Bridges read a whole family of variables from outside themselves -
matrix_bridges_relay_enabled, _encryption_enabled, _encryption_default,
_msc4190_enabled, _self_sign_enabled, plus matrix_admin - all defined in
matrix-base. Since every bridge reads them, they belong in shared context
rather than in each bridge's scenario: molecule-shared/playbook-context.yml
now carries them along with the identity and path variables the first
scenario had inline. Note it is loaded through vars_files, which outranks
inventory group_vars, so it is authoritative; a scenario that wants to prove
one of these reaches the rendered configuration should say so explicitly.

Appservices call /whoami while starting and refuse to run if the id returned
is not the bot user they were configured as - mautrix-whatsapp exits 17 with
"Unexpected user ID in whoami call". The shared stub now takes the id it
should claim to be. Expect every bridge and bot to need this.

What the scenario proves: the bridge starts and stays up, opens its
appservice port, its rendered config and appservice registration carry the
scenario's tokens and bot user, it created its sqlite database under the
role's data path as the role's uid, and it runs the version the role pins.
It does not bridge anything and never will.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Not for merging as-is. One role's scenario plus the workflow that would
make per-role testing affordable here, so we can see how it behaves before
deciding whether to do the other 69.

Unlike the MASH repositories, one repository holds every role, so running
everything on every push is not an option. The workflow's first job works
out which roles a push touched and builds the matrix from that; a change to
docs, or to a role with no scenario yet, runs nothing.

Three things this role needed that a MASH role does not:

- The variables matrix-base would supply (matrix_base_data_path,
  matrix_domain, matrix_user_name, matrix_group_name and the uid/gid) have
  to be provided by the scenario, and the user and group have to exist
  before the role's file tasks run.
- The service contacts the homeserver while starting up - it fetches
  /_matrix/client/v3/joined_rooms to resolve its room mapping and exits 1
  if that fails - so prepare.yml stands up a stub homeserver. Most roles
  here are bridges and bots, so this is likely the rule rather than the
  exception.
- verify.yml runs as its own play, where role defaults are out of scope, so
  the paths it reads are pinned in molecule.yml. The version is deliberately
  NOT pinned: it is read from defaults/main.yml so the assertion compares
  the running image against what the role ships.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>