Root cause: handleStatus built forwards only from local SQLite links table;
handleCanvasGet returned only local store data. Neither merged the ring
topology (which IS synced to every node in-memory). Result: non-claiming
nodes saw only their own claimed forwards, not the full cluster.
Fix: read-time merge in both handlers — iterate ring topology entries and
add any (local, remote, link) not already in the local store. No store
writes (avoids the per-forward stop/start issue that broke the old
topology-derived-canvas model).
Verified: all 4 cluster nodes now show 5 forwards / 4 remotes / 5 links;
isolated node-e correctly shows empty.
