Add agent memory example for hybrid context retrieval

[CalebKiragu]

Summary

• Add a runnable agent-memory SQL example over ordinary Postgres tables (users, sessions, decisions) with filtered dense search, hybrid retrieval (pgcontext.query), and a hydrated context pack for LLM prompts.
• Add scripts/quickstart.sh agent-memory, playground script, and user guide so the hosted Memory demo story is reproducible from the OSS checkout.

Motivation

Polygres markets Postgres-as-agent-memory, but the open-source quickstart did not yet show how to model durable decision memory or run hybrid retrieval locally. This closes that adoption gap without touching extension internals.

Implementation

• examples/sql/06_agent_memory.sql — full walkthrough with 4-D fixture embeddings
• playground/agent_memory.sql — Docker-friendly demo with stage output
• docs/user_guide/agent_memory.md — schema, walkthrough, optional GraphRAG appendix
• scripts/quickstart.sh agent-memory — one-command local run

Benefits

• Developers can reproduce the Memory demo in ~5 minutes with Docker only
• Shows the product thesis in SQL: rows + embeddings + scoped filters = queryable agent memory
• Low-risk docs/example PR; no Rust or HNSW changes

Tradeoffs

• Uses fixture vectors, not a live embedding model (documented explicitly)
• GraphRAG composition is documented as optional appendix, not a fused API

Testing

docker run -d --name pgcontext-review \
  -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=postgres -e POSTGRES_DB=pgcontext \
  -p 5433:5432 ghcr.io/evokoa/pgcontext:pg17-v0.2.0

PGPASSWORD=postgres psql -h 127.0.0.1 -p 5433 -U postgres -d pgcontext \
  -f playground/agent_memory.sql

Verified locally: filtered billing search returns d-billing-refund; hybrid search ranks billing decision first; context pack hydrates summary + session topic.

python3 scripts/check-public-docs.py --check

Future work

• Companion SDK example in Evokoa/polygres-sdk (separate PR)
• Dual-extension Compose playground when graph-augmented retrieval APIs land

Made with Cursor