fix: pgvector deployment — idempotent migration, pgvector image, schema sync

- docker-compose.yml: switch postgres:16-alpine to pgvector/pgvector:pg16
- migration: rewrite with IF NOT EXISTS guards, DO block for safe
  text→vector(1536) conversion, handles partial/re-run states
- schema.prisma (both): add @default(now()) on NoteEmbedding.updatedAt,
  sync mcp-server embedding type to Unsupported("vector(1536)")
- deploy.yaml: add docker compose pull postgres before build

memento-note/prisma/migrations/20260512120000_pgvector_and_fts_search/migration.sql

@@ -1,38 +1,71 @@
 -- Phase 1: Enable pgvector extension
 CREATE EXTENSION IF NOT EXISTS vector;
 
--- Phase 2: Add native vector column to NoteEmbedding
--- Convert existing JSON-string embeddings to native vector(1536)
-ALTER TABLE "NoteEmbedding" ADD COLUMN "vec" vector(1536);
+-- Phase 2: Convert embedding column from text/JSON to vector(1536) if needed
+DO $$
+DECLARE
+    _udt text;
+    _vec_tmp_exists boolean;
+BEGIN
+    SELECT udt_name INTO _udt
+    FROM information_schema.columns
+    WHERE table_schema = 'public'
+      AND table_name = 'NoteEmbedding'
+      AND column_name = 'embedding';
 
--- Migrate existing data: parse JSON arrays into pgvector format
-UPDATE "NoteEmbedding"
-SET "vec" = ("embedding"::jsonb)::text::vector(1536)
-WHERE "embedding" IS NOT NULL;
+    IF _udt IS NOT NULL AND _udt != 'vector' THEN
+        SELECT EXISTS (
+            SELECT 1 FROM information_schema.columns
+            WHERE table_schema = 'public'
+              AND table_name = 'NoteEmbedding'
+              AND column_name = '_vec_tmp'
+        ) INTO _vec_tmp_exists;
 
--- Drop old string column, rename new one
-ALTER TABLE "NoteEmbedding" DROP COLUMN "embedding";
-ALTER TABLE "NoteEmbedding" RENAME COLUMN "vec" TO "embedding";
+        IF NOT _vec_tmp_exists THEN
+            ALTER TABLE "NoteEmbedding" ADD COLUMN "_vec_tmp" vector(1536);
+        END IF;
 
--- Add updatedAt column for tracking reindex freshness
-ALTER TABLE "NoteEmbedding" ADD COLUMN "updatedAt" TIMESTAMP NOT NULL DEFAULT now();
+        UPDATE "NoteEmbedding"
+        SET "_vec_tmp" = ("embedding"::jsonb)::text::vector(1536)
+        WHERE "embedding" IS NOT NULL
+          AND "_vec_tmp" IS NULL;
+
+        ALTER TABLE "NoteEmbedding" DROP COLUMN "embedding";
+        ALTER TABLE "NoteEmbedding" RENAME COLUMN "_vec_tmp" TO "embedding";
+    ELSIF _udt IS NULL THEN
+        SELECT EXISTS (
+            SELECT 1 FROM information_schema.columns
+            WHERE table_schema = 'public'
+              AND table_name = 'NoteEmbedding'
+              AND column_name = '_vec_tmp'
+        ) INTO _vec_tmp_exists;
+
+        IF _vec_tmp_exists THEN
+            ALTER TABLE "NoteEmbedding" RENAME COLUMN "_vec_tmp" TO "embedding";
+        END IF;
+    END IF;
+END $$;
+
+-- Add updatedAt with DEFAULT NOW() if not present
+ALTER TABLE "NoteEmbedding" ADD COLUMN IF NOT EXISTS "updatedAt" TIMESTAMP(3) NOT NULL DEFAULT NOW();
 
 -- HNSW index for fast approximate nearest neighbor search (cosine distance)
-CREATE INDEX "NoteEmbedding_embedding_hnsw_idx" ON "NoteEmbedding"
+CREATE INDEX IF NOT EXISTS "NoteEmbedding_embedding_hnsw_idx" ON "NoteEmbedding"
   USING hnsw ("embedding" vector_cosine_ops)
   WITH (m = 16, ef_construction = 64);
 
 -- Phase 3: Add full-text search tsvector column to Note
-ALTER TABLE "Note" ADD COLUMN "tsv" tsvector;
+ALTER TABLE "Note" ADD COLUMN IF NOT EXISTS "tsv" tsvector;
 
--- Populate tsv from existing title + content
+-- Populate tsv where still NULL
 UPDATE "Note"
 SET "tsv" =
   setweight(to_tsvector('simple', COALESCE("title", '')), 'A') ||
-  setweight(to_tsvector('simple', COALESCE("content", '')), 'B');
+  setweight(to_tsvector('simple', COALESCE("content", '')), 'B')
+WHERE "tsv" IS NULL;
 
 -- GIN index for fast FTS queries
-CREATE INDEX "Note_tsv_gin_idx" ON "Note" USING gin ("tsv");
+CREATE INDEX IF NOT EXISTS "Note_tsv_gin_idx" ON "Note" USING gin ("tsv");
 
 -- Trigger function to auto-update tsv on INSERT or UPDATE of title/content
 CREATE OR REPLACE FUNCTION "note_tsv_trigger"() RETURNS trigger AS $$
@@ -44,7 +77,7 @@ BEGIN
 END;
 $$ LANGUAGE plpgsql;
 
--- Attach trigger
+-- Attach trigger (DROP IF EXISTS + CREATE is idempotent)
 DROP TRIGGER IF EXISTS "note_tsv_update" ON "Note";
 CREATE TRIGGER "note_tsv_update"
   BEFORE INSERT OR UPDATE OF "title", "content" ON "Note"

memento-note/prisma/schema.prisma

@@ -302,7 +302,7 @@ model NoteEmbedding {
   noteId    String   @unique
   embedding Unsupported("vector(1536)")
   createdAt DateTime @default(now())
-  updatedAt DateTime @updatedAt
+  updatedAt DateTime @default(now()) @updatedAt
   note      Note     @relation(fields: [noteId], references: [id], onDelete: Cascade)
 
   @@index([noteId])