Second of six subtasks of AZ-618. Extends
airborne_bootstrap.build_pre_constructed(config) additively with the
two C6 storage entries on top of AZ-619's c13_fdr + clock contract:
- c6_descriptor_index: via storage_factory.build_descriptor_index
- c6_tile_store: via storage_factory.build_tile_store
When BUILD_FAISS_INDEX=OFF, the lower-level RuntimeNotAvailableError
from the descriptor index factory is translated into an
AirborneBootstrapError that names the missing key
(c6_descriptor_index), the gating flag (BUILD_FAISS_INDEX), and the
consuming component slug(s) drawn from
AIRBORNE_REQUIRED_PRE_CONSTRUCTED_KEYS. The original error is
preserved as __cause__ so operators still see the upstream reason.
Tests: 3 new unit tests cover AC-620.1 + AC-620.2 (twice, with and
without a configured consumer, so the bootstrap fails loudly in
either branch). AZ-619 tests updated to add an autouse stub for the
Phase B builders (keeps them focused on Phase A keys) and to relax
the "exactly two keys" assertion to "AZ-619 keys remain present
under AZ-620 additivity" per the original test's own forward-pointer.
Bonus: ruff --fix removed 12 pre-existing UP037 quoted-annotation
warnings in airborne_bootstrap.py (covered by `from __future__ import
annotations`). All in modified-area scope per quality-gates.mdc.
Run: pytest tests/unit/runtime_root/ -q -> 15/15 passed in 1.06s.
Spec moved to _docs/02_tasks/done/ in the previous commit (audit-trail
backfill of batch_90 also landed there).
Co-authored-by: Cursor <cursoragent@cursor.com>
Oleksandr Bezdieniezhnykh