Get Kg Node Debug

Return current_values, full history, and active edges for one KG node.

shop_id comes from the session via kg_read_shop_id (agents.md rule #7 — never from a request argument).

All reads are non-mutating. Returns empty lists for unknown canonical_ids — the node may exist in kg_nodes without shadow-writes yet.

History rows are annotated with deprecated=True when their (fact_type, value) pair appears in entity_fact_deprecations, so callers can see which observations are suppressed from the current_values() projection.

FINANCIAL GATE (kg-debugger-view task §0, 2026-07-02): unit_price facts are dropped from both current_values and history unless shop.security_class == 'financial' — the same gate /internal/kg/node/{id} applies, shared via core.services.kg.read.security_gates so this endpoint can't silently drift out of sync with it again.

node_type/display_name/observation_count (kg-debugger-view task, 2026-07-02): fetched from kg_nodes_repo and included ADDITIVELY so the ported renderer's node inspector has a type/label/badge for its header — this endpoint previously never looked up the node row at all, only its facts and edges. None when the node isn't found (unchanged behavior).