feat: Phase 6 complete — chat, multi-group, federation, replication, webcrypto

6.1 Double Ratchet (meshbay_common/ratchet.py):
  Forward secrecy, break-in recovery, out-of-order delivery.
  Signal-spec KDF_RK/KDF_CK via HKDF-SHA256. 11/11 tests.

6.2 Multi-group node (config.py):
  [[groups]] TOML array, per-group ports, back-compat [group].

6.3 MHP federation persistence (db/models.py FederatedGroup + SwarmSource):
  receive_directory() now persists to federated_groups table.
  list_public_groups() includes federated results with source attribution.

6.4 Content replication (node/replication.py + hub SwarmSource):
  ContentReplicator: fetch-index, download, hash-verify, register-swarm.
  Hub: POST /v1/swarm/register, GET /v1/swarm/{hash} for multi-source.

6.5 Browser private group (webcrypto.py + static/crypto.js):
  AES-256-GCM variant of GEK for WebCrypto-compatible groups.
  crypto.js: SubtleCrypto importGEK + deriveChunkKey + decryptChunk.
  Keys distinct from ChaCha20 via :aes HKDF info suffix. 4/4 tests.

74/74 tests total.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

1 files changed, 24 insertions, 4 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/api/federation.py b/packages/meshbay-hub/src/meshbay_hub/api/federation.py
index 5a7f45f..88bb645 100644
--- a/packages/meshbay-hub/src/meshbay_hub/api/federation.py
+++ b/packages/meshbay-hub/src/meshbay_hub/api/federation.py
@@ -36,6 +36,7 @@ from meshbay_hub.api.deps import get_current_user
 from meshbay_hub.auth import _hub_id, _hub_sk_pem, hub_public_key_pem
 from meshbay_hub.db.engine import get_db
 from meshbay_hub.db.models import Group, User
+from sqlalchemy.ext.asyncio import AsyncSession
 
 log = logging.getLogger(__name__)
 
@@ -141,19 +142,38 @@ class DirectoryPayload(BaseModel):
 async def receive_directory(
     body: DirectoryPayload,
     authorization: str = Header(...),
+    db: AsyncSession = Depends(get_db),
 ):
     """
     Receive a Mesh Directory update from a peer hub.
-    The directory is stored in memory (production: DB table federated_groups).
+    Persists groups to federated_groups table for cross-hub search.
     """
     try:
         _verify_mhp_token(authorization.removeprefix("Bearer "))
     except Exception as e:
         raise HTTPException(status_code=401, detail=str(e))
 
-    log.info("Received %d groups from hub %s", len(body.groups), body.hub_id[:16])
-    # TODO Phase 5+: persist to federated_groups table, make searchable
-    return {"accepted": len(body.groups), "from_hub": body.hub_id}
+    from meshbay_hub.db.models import FederatedGroup
+    from datetime import datetime, timezone
+    now = datetime.now(timezone.utc)
+    count = 0
+    for g in body.groups:
+        existing = await db.get(FederatedGroup, g["id"])
+        if existing:
+            existing.name        = g.get("name", existing.name)
+            existing.join_policy = g.get("join_policy", existing.join_policy)
+            existing.updated_at  = now
+        else:
+            db.add(FederatedGroup(
+                id=g["id"],
+                name=g.get("name", ""),
+                source_hub=body.hub_id,
+                join_policy=g.get("join_policy", "invite"),
+            ))
+        count += 1
+    await db.commit()
+    log.info("Persisted %d groups from hub %s", count, body.hub_id[:16])
+    return {"accepted": count, "from_hub": body.hub_id}
 
 
 # ── Revocation propagation ────────────────────────────────────────────────────