`/api/layout` does not expose edge `confidence`

[avigdorsky]

Severity: medium.

CALLS edges carry confidence, strategy, candidates, via via query_graph,
but the layout endpoint returns only {source, target, type} — 0 of ~208 000 edges
carry confidence. The graph UI therefore cannot distinguish an LSP-resolved call
from a suffix_match guess, and neither can any HTTP consumer.

Ask: include confidence and strategy on layout edges, ideally with a
min_confidence query parameter.

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Observed on v0.10.8 (build 996bad5fe6fb), macOS arm64, Python monorepo (~36k nodes / ~179k edges). Happy to provide a minimal reproduction repo if useful.