feat(plane): memory store (file and MinIO) and the remember task (harnessx-removal task 2)

plane/memory.py: the MemoryStore interface with FileStore (index.jsonl, facts by
content hash, repos/<host>__<owner>__<name>/<pin>.jsonl, idempotent ingest,
deterministic row ids, refusal below 1 GiB free naming the path) and MinioStore
(object metadata and tags, S3 Select pushdown probed once per process with a
logged local fallback, object version ids on every row read, versioning and
runs/ lifecycle helper, presigned URLs). OUSAST_MEMORY selects the backend;
MINIO_* settings come from .env; the minio SDK is the optional extra `minio`.

plane/tasks/remember.py: model-free rows (facts, verdict, unit_cost, alert)
from a case's artifacts; remember_run computes them on the host for a recorded
run without writing into it. reconciler.mark_done (477 lines total), seed
before and ingest after `ousast plane run`, `ousast plane remember <run>`.
The generator annotates each repo-facts Task with openultrasast.io/memory-key
(repo, pin, candidates digest, image digest) and the Run with its population
and split; plane/ regenerated.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

.kiro/specs/harnessx-removal/tasks.md

@@ -12,7 +12,7 @@ and passed its fixture test. Every task is a commit gated on the full suite's ow
     written next to it.
   - _Requirements: 3.1, 5.1_
 
-- [ ] 2. Memory store and the `remember` task
+- [x] 2. Memory store and the `remember` task
   - `plane/memory.py`: the `MemoryStore` interface with `FileStore` and `MinioStore` (object metadata/tags,
     S3 Select JSON queries probed with a local fallback, versioned provenance, lifecycle, presign stubs;
     `OUSAST_MEMORY` selects; MinIO settings from `.env`; `minio` SDK as an optional extra); JSON rows per