Fix Docker build: use prebuilt postgresql-17-pgvector from official APT repo

Dockerfile

@@ -1,17 +1,17 @@
 FROM python:3.11-slim
 
-RUN apt-get update && apt-get install -y \
-    postgresql \
-    postgresql-contrib \
-    libpq-dev \
-    build-essential \
-    git \
+# Add official PostgreSQL APT repo (provides postgresql-17-pgvector prebuilt)
+RUN apt-get update && apt-get install -y gnupg2 curl \
+    && curl -fsSL https://www.postgresql.org/media/keys/ACCC4CF8.asc \
+       | gpg --dearmor -o /usr/share/keyrings/postgresql-keyring.gpg \
+    && echo "deb [signed-by=/usr/share/keyrings/postgresql-keyring.gpg] http://apt.postgresql.org/pub/repos/apt bookworm-pgdg main" \
+       > /etc/apt/sources.list.d/postgresql.list \
+    && apt-get update && apt-get install -y \
+       postgresql-17 \
+       postgresql-17-pgvector \
+       libpq-dev \
     && rm -rf /var/lib/apt/lists/*
 
-RUN git clone --branch v0.8.0 https://github.com/pgvector/pgvector.git /pgvector \
-    && cd /pgvector && make && make install \
-    && rm -rf /pgvector
-
 WORKDIR /app
 
 COPY requirements.txt .