The provenance basis of an edge — where the evidence comes from. This is the synaptic
strength signal: Resolved edges (from syntax/authoring) are trusted and strong;
Lexical edges (from co-occurrence heuristics) are candidates, weak until verified.
The activation ranker uses this as the base weight: Resolved=1.0, Lexical=0.4.
From syntax or explicit authoring (wikilinks, impl, contains, frontmatter relations).
Trusted — walked during context expansion. Synaptic weight: 1.0. Must be claimed
explicitly at the edge builder; it is NEVER the default (trust is earned, not inherited).
From lexical co-occurrence heuristics (mentions, references). Untrusted — not walked
in expansion, but available as a candidate signal. Synaptic weight: 0.4. This is the
DEFAULT: an edge builder that forgets to set basis gets the safe, untrusted band.