feat(harness): port vectorstore dual-key + reader RPC (D11, §5.4)

Ports vectorstore/{rest_client,rest_writer,store,reader,embeddings,records},
evidence/model (leaf dep of records), and cli/_guards (require_vector_write_allowed
workstation write-guard). Renamed psdwp3->nsp, verbatim.

VectorRestClient gains an api_key property so reader/writer clients carry their
distinct keys visibly (spec D11: vector_reader / vector_writer on the same endpoint).

scripts/create_vector_reader_rpc.sql is NEW: the reader RPCs (search_similar,
list_tables) lived server-side in Supabase and were never versioned. Authored now
mirroring the writer allowlist pattern (table allowlist, security definer, revoke
from anon/authenticated, grant to vector_reader only). Writer RPC ported verbatim.

L1: test_vector_dual_key (7 tests) pins the dual-key construction + the workstation
write-guard (exit 4 without writer key).

harness/scripts/create_vector_writer_rpc.sql

@@ -0,0 +1,126 @@
+-- RPC writer controllate per pgvector via Supabase/PostgREST.
+-- Eseguire sul database Supabase centrale come owner dello schema `vectors`.
+-- Prerequisiti:
+--   - schema `vectors` con tabelle schema_records/evidence/memory
+--   - colonne: record_key text unique, kind text, content_hash text, metadata jsonb,
+--     embedding vector(N), indexed_at timestamptz
+--   - ruolo/key PostgREST dedicato `vector_writer`
+--
+-- La key writer deve ricevere solo EXECUTE su queste funzioni, non privilegi raw di DELETE
+-- sulle tabelle. Cleanup/rebuild restano via terminale sul server.
+
+create or replace function public._assert_vector_write_table(table_name text, kinds text[])
+returns void
+language plpgsql
+stable
+as $$
+begin
+  if table_name not in ('schema_records', 'evidence', 'memory') then
+    raise sqlstate 'PGRST' using
+      message = json_build_object('message', 'Unsupported vector table')::text,
+      detail = json_build_object('status', 400)::text;
+  end if;
+
+  if table_name = 'schema_records'
+     and exists (select 1 from unnest(kinds) k where k not in ('schema_table', 'schema_column')) then
+    raise sqlstate 'PGRST' using
+      message = json_build_object('message', 'Invalid kind for schema_records')::text,
+      detail = json_build_object('status', 400)::text;
+  elsif table_name = 'evidence'
+     and exists (select 1 from unnest(kinds) k where k <> 'evidence') then
+    raise sqlstate 'PGRST' using
+      message = json_build_object('message', 'Invalid kind for evidence')::text,
+      detail = json_build_object('status', 400)::text;
+  elsif table_name = 'memory'
+     and exists (select 1 from unnest(kinds) k where k <> 'memory') then
+    raise sqlstate 'PGRST' using
+      message = json_build_object('message', 'Invalid kind for memory')::text,
+      detail = json_build_object('status', 400)::text;
+  end if;
+end;
+$$;
+
+create or replace function public.existing_vector_hashes(table_name text, kinds text[])
+returns table(record_key text, content_hash text)
+language plpgsql
+security definer
+set search_path = public, vectors, extensions
+as $$
+begin
+  perform public._assert_vector_write_table(table_name, kinds);
+  return query execute format(
+    'select record_key, content_hash from vectors.%I where kind = any ($1)',
+    table_name
+  ) using kinds;
+end;
+$$;
+
+create or replace function public.upsert_vector_records(table_name text, rows jsonb)
+returns jsonb
+language plpgsql
+security definer
+set search_path = public, vectors, extensions
+as $$
+declare
+  r jsonb;
+  affected integer := 0;
+  kinds text[];
+begin
+  if jsonb_typeof(rows) <> 'array' then
+    raise sqlstate 'PGRST' using
+      message = json_build_object('message', 'rows must be a JSON array')::text,
+      detail = json_build_object('status', 400)::text;
+  end if;
+
+  select coalesce(array_agg(distinct value->>'kind'), array[]::text[])
+    into kinds
+  from jsonb_array_elements(rows) value;
+  perform public._assert_vector_write_table(table_name, kinds);
+
+  for r in select * from jsonb_array_elements(rows) loop
+    execute format(
+      'insert into vectors.%I (record_key, kind, content_hash, metadata, embedding)
+       values ($1, $2, $3, $4::jsonb, $5::vector)
+       on conflict (record_key) do update set
+         kind = excluded.kind,
+         content_hash = excluded.content_hash,
+         metadata = excluded.metadata,
+         embedding = excluded.embedding,
+         indexed_at = now()',
+      table_name
+    ) using
+      r->>'record_key',
+      r->>'kind',
+      r->>'content_hash',
+      coalesce(r->'metadata', '{}'::jsonb),
+      ('[' || (select string_agg(value::text, ',') from jsonb_array_elements(r->'embedding')) || ']');
+    affected := affected + 1;
+  end loop;
+
+  return jsonb_build_object('upserted', affected);
+end;
+$$;
+
+revoke all on function public._assert_vector_write_table(text, text[]) from public;
+revoke all on function public.existing_vector_hashes(text, text[]) from public;
+revoke all on function public.upsert_vector_records(text, jsonb) from public;
+
+-- Su alcuni progetti Supabase le funzioni in `public` ricevono grant automatici: revoca
+-- esplicitamente dai ruoli client generici, poi abilita solo il writer dedicato.
+do $$
+begin
+  if exists (select 1 from pg_roles where rolname = 'anon') then
+    revoke all on function public.existing_vector_hashes(text, text[]) from anon;
+    revoke all on function public.upsert_vector_records(text, jsonb) from anon;
+  end if;
+  if exists (select 1 from pg_roles where rolname = 'authenticated') then
+    revoke all on function public.existing_vector_hashes(text, text[]) from authenticated;
+    revoke all on function public.upsert_vector_records(text, jsonb) from authenticated;
+  end if;
+  if exists (select 1 from pg_roles where rolname = 'vector_writer') then
+    grant execute on function public.existing_vector_hashes(text, text[]) to vector_writer;
+    grant execute on function public.upsert_vector_records(text, jsonb) to vector_writer;
+  end if;
+end $$;
+
+notify pgrst, 'reload schema';