Add engram_auto_link_semantic(): when a node is embedded, scan all
embedded nodes for cosine sim >= 0.72 and create bidirectional
"semantic-similar" edges to the top-3 matches. Runs once at write
time rather than at every query, converting the expensive O(N) scan
from live activation into durable graph structure.
Fixes the core connectivity problem: 63 edges / 5364 nodes (0.012
edges/node). Verified: new Knowledge nodes now auto-link at sim 0.77–
0.95 with correct threshold discrimination. One checkpoint per insert
(not one per edge) bounds the persistence overhead.
Excludes InternalStateEvents and inbox/outbox transient nodes to keep
semantic graph clean.
will.anderson
8f922e68b3