Remove `tags_required: [airouter-eligible]` from airouter-impl-ready so all
non-skip tasks route through the full airouter→sonnet→opus ladder automatically.
Add `airouter-skip` to airouter's tags_forbidden so opt-out tasks go directly
to sonnet from attempt 0.
Relax sonnet-impl-ready tags_forbidden (drop multi-file + algorithmic-large)
so sonnet handles complex tasks at escalation tier without template rejection.
Add opus-impl-ready@1.yaml — last-resort escalation, code-opus-tdd-repo
composite, scope_budget 5 files / 400 lines / 3600s.
a12f6ddaba