compose: switch missions_workspaces to host bind-mount

Named docker volume required the separately-managed clawmates-runtime
container to know the volume's on-disk path (varies by docker root).
A predictable host path (/var/lib/clawmates-missions) means the
runtime's spawn command can bind-mount the same path directly.

deploy/compose/docker-compose.yml

@@ -28,11 +28,12 @@ volumes:
   # the unix-socket equivalent of the K8s sidecar topology.
   broker_run: {}
   broker_key: {}
-  # Per-mission repo checkouts + generated PDFs. Server writes to
+  # Per-mission repo checkouts + generated PDFs live on the host at
-  # this via mission_workspace + pdf_renderer; the (separately-managed)
+  # /var/lib/clawmates-missions so the (separately-managed)
-  # clawmates-runtime container bind-mounts the same path so scans
+  # clawmates-runtime container can bind-mount the SAME host path and
-  # + benches exec at the same tree.
+  # see the same tree the server wrote to. A named docker volume
-  missions_workspaces: {}
+  # would work too but would need volume-name knowledge in the
+  # runtime's spawn command.
 
 services:
   postgres:
@@ -131,7 +132,7 @@ services:
       # Per-mission repo checkouts. Bind-mounted host path so the
       # separately-managed clawmates-runtime container can see the
       # same trees at the same path when it exec's for scans/benches.
-      - missions_workspaces:/var/lib/clawmates-missions
+      - /var/lib/clawmates-missions:/var/lib/clawmates-missions
     networks: [edge, core, engine_net]
     ports:
       - "8080:8080"