feat: implement get_channel factory for XMPP channel (M10-U6)
get_channel(settings, dry_run=False) -> Channel | None with:
- enabled=False → None (no warning, no exception)
- enabled=True + missing jid/password/to/host → redacted warning log, None
- enabled=True + complete config → SyncXmppChannel instance
- Factory never raises exceptions (D2 non-blocking degradation)
- redact_secrets with extra_secrets=[password, jid, to] on warning logs
Re-exports Channel, XmppChannel, SyncXmppChannel from channels package.
19 unit tests covering disabled, misconfigured, complete, dry-run, and
secret-safe warning log scenarios.
Co-authored-by: opencode/test-engineer <test-engineer@agents.invalid>
Co-authored-by: opencode/coder <coder@agents.invalid>
Antoine Van Elstraete
e07a6d709d
