feat: pgvector extension + incidents.embedding column + match_incidents RPC

supabase/migrations/20260711000012_pgvector.sql

@@ -0,0 +1,42 @@
+-- Enable pgvector
+create extension if not exists vector;
+
+-- Add embedding column to incidents (nullable — populated async after creation)
+alter table incidents
+  add column if not exists embedding vector(1024);
+
+-- IVFFlat index for cosine similarity (10 lists sufficient for <10k rows)
+create index if not exists incidents_embedding_idx
+  on incidents using ivfflat (embedding vector_cosine_ops)
+  with (lists = 10);
+
+-- Similarity search — returns top-N most similar incidents (cosine)
+create or replace function match_incidents(
+  query_embedding vector(1024),
+  exclude_id      uuid,
+  match_count     int default 5
+)
+returns table (
+  id            uuid,
+  reference_no  text,
+  incident_type text,
+  description   text,
+  severity      int,
+  similarity    float
+)
+language sql
+security definer
+as $$
+  select
+    i.id,
+    i.reference_no,
+    i.incident_type,
+    i.description,
+    i.severity,
+    1 - (i.embedding <=> query_embedding) as similarity
+  from incidents i
+  where i.id != exclude_id
+    and i.embedding is not null
+  order by i.embedding <=> query_embedding
+  limit match_count;
+$$;