Implement AGENTIC-WP-0011 kaizen correlation follow-up

Add bidirectional doc links (PRD §9.1, README, DESIGN §11), session-close
HELIX_* env convention, stable digest JSON contract, and digest_lookup CLI
for read-only correlate lookups. All tasks done; 163 tests green.

session_memory/README.md

@@ -45,6 +45,7 @@ session_memory/
   retro/build.py       # windowed top-3-per-repo suggestions
   retro/publish.py     # hub coding_retro read model + local report
   retro/__main__.py    # python -m session_memory.retro
+  digest_lookup.py     # python -m session_memory.digest_lookup (read one digest, no ingest)
   config.toml          # store paths, retention caps, sources, repo->domain map, curate gate
 ```
 
@@ -184,6 +185,39 @@ Writes `retro/last_retro.{json,md}` and (with `--publish`) posts an
 which emits one improvement task per relevant repo. Hub publish degrades
 gracefully when the hub is unreachable.
 
+## Correlation with kaizen-agentic
+
+Helix Forge owns **fleet-level** session digests; **kaizen-agentic** owns
+**project-scoped** execution metrics (ADR-004). The two layers correlate by
+optional `helix_session_uid` on project records — **link-by-reference only**;
+kaizen-agentic does not ingest JSONL into this store.
+
+| Layer | Storage |
+|-------|---------|
+| Fleet (here) | `session_memory/.store/mem.db` → `digests` table |
+| Project (kaizen) | `.kaizen/metrics/<agent>/executions.jsonl` |
+
+- **Spec:** [DESIGN-session-memory.md §11](../docs/DESIGN-session-memory.md#11-project-metrics-correlation-kaizen-agentic)
+- **Contract (kaizen-agentic):** [Helix Forge Correlation Contract](https://gitea.coulomb.social/coulomb/kaizen-agentic/src/branch/main/docs/integrations/helix-forge-correlation.md)
+
+### Session-close env export
+
+After ingest has written the digest, agents using both layers export `HELIX_*`
+vars for `kaizen-agentic metrics record` to merge (names match ADR-004):
+
+`HELIX_SESSION_UID`, `HELIX_REPO`, `HELIX_FLAVOR`, `HELIX_TOKENS`,
+`HELIX_INFRA_OVERHEAD_SHARE`, and optionally `HELIX_STORE_DB` (absolute path to
+`mem.db`). See DESIGN §11.1 for field sources.
+
+### Read one digest (for `metrics correlate`)
+
+```bash
+python -m session_memory.digest_lookup claude:abc-123 --json
+HELIX_STORE_DB=/abs/path/to/mem.db python -m session_memory.digest_lookup <uid>
+```
+
+Defaults to `[store].db_path` in `config.toml`. Read-only — does not run ingest.
+
 ## Retention knobs (`[retention]` in config.toml)
 
 | Key | Meaning |
@@ -220,3 +254,7 @@ python -m pytest          # schema, adapters, store, digest, retention, ingest,
 - **Phase 4** (AGENTIC-WP-0009): Measure — fleet baseline/trend + before/after
   per-pattern effectiveness. The Capture → Detect → Curate → Distribute → Measure
   loop is closed.
+- **Weekly retro** (AGENTIC-WP-0010): windowed top-3-per-repo + hub `coding_retro`
+  publish.
+- **Kaizen correlation** (AGENTIC-WP-0011): bidirectional doc links, session-close
+  `HELIX_*` env convention, `digest_lookup` read path.

session_memory/digest_lookup.py

@@ -0,0 +1,76 @@
+"""Read a single session digest from the local store (AGENTIC-WP-0011 T03).
+
+Thin read path for ``kaizen-agentic metrics correlate`` and other consumers.
+Does not run ingest.
+
+Usage:
+    python -m session_memory.digest_lookup <session_uid> [--json]
+    HELIX_STORE_DB=/abs/path/to/mem.db python -m session_memory.digest_lookup <uid>
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import sys
+
+from .core.store import Store
+from .ingest import _expand, load_config
+
+
+def resolve_store_paths(*, config_path: str | None = None) -> tuple[str, str]:
+    """Resolve db + blob paths from HELIX_STORE_DB or config.toml [store]."""
+    env_db = os.environ.get("HELIX_STORE_DB")
+    if env_db:
+        db_path = _expand(env_db)
+        blob_dir = os.path.join(os.path.dirname(db_path), "blobs")
+        return db_path, blob_dir
+
+    here = os.path.dirname(os.path.abspath(__file__))
+    cfg_path = config_path or os.path.join(here, "config.toml")
+    store_cfg = load_config(cfg_path).get("store", {})
+    return _expand(store_cfg.get("db_path", "session_memory/.store/mem.db")), _expand(
+        store_cfg.get("blob_dir", "session_memory/.store/blobs")
+    )
+
+
+def lookup_digest(session_uid: str, *, config_path: str | None = None) -> dict | None:
+    db_path, blob_dir = resolve_store_paths(config_path=config_path)
+    store = Store(db_path, blob_dir)
+    try:
+        return store.get_digest(session_uid)
+    finally:
+        store.close()
+
+
+def main(argv: list[str] | None = None) -> int:
+    here = os.path.dirname(os.path.abspath(__file__))
+    ap = argparse.ArgumentParser(
+        description="Read one session digest from the Helix Forge store (no ingest)."
+    )
+    ap.add_argument("session_uid", help="Normalized session uid, e.g. claude:abc-123")
+    ap.add_argument("--config", default=os.path.join(here, "config.toml"),
+                    help="config.toml when HELIX_STORE_DB is unset")
+    ap.add_argument("--json", action="store_true", help="print digest JSON to stdout")
+    args = ap.parse_args(argv)
+
+    digest = lookup_digest(args.session_uid, config_path=args.config)
+    if digest is None:
+        print(f"digest not found: {args.session_uid}", file=sys.stderr)
+        return 1
+
+    if args.json:
+        print(json.dumps(digest, indent=2, sort_keys=True))
+    else:
+        cost = digest.get("cost") or {}
+        tokens = cost.get("input_tokens", 0) + cost.get("output_tokens", 0)
+        print(f"session_uid: {digest.get('session_uid')}")
+        print(f"repo: {digest.get('repo')}  flavor: {digest.get('flavor')}")
+        print(f"outcome: {digest.get('outcome')}  tokens: {tokens}")
+        print(f"started_at: {digest.get('started_at')}  ended_at: {digest.get('ended_at')}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())