feat: standalone claude-memory-mcp with multi-user support and Vault integration

Extracted from private infra repo into standalone open-source project.

Three operating modes:
- Local: SQLite + FTS5 (zero dependencies)
- Server: PostgreSQL via HTTP API with multi-user auth
- Full: PostgreSQL + HashiCorp Vault for secret management

Features:
- MCP stdio server with 5 tools (store/recall/list/delete/secret_get)
- FastAPI HTTP API with multi-user Bearer token auth (API_KEYS JSON map)
- Regex-based credential detection with auto-redaction
- AES-256-GCM encryption fallback for non-Vault deployments
- Vault KV v2 client (stdlib urllib, K8s SA auto-auth)
- Per-user data isolation (all queries scoped by user_id)
- Secret migration endpoint for existing plain-text credentials
- Backward-compatible env var aliases (CLAUDE_MEMORY_API_URL)

Infrastructure:
- Docker + docker-compose (API + PostgreSQL + optional Vault)
- Woodpecker CI (test → build → push → kubectl deploy)
- GitHub Actions CI (Python 3.11/3.12/3.13) + Release (GHCR + PyPI)
- Helm chart + raw Kubernetes manifests

96 tests passing across 6 test files.

docker/Dockerfile

@@ -0,0 +1,15 @@
+FROM python:3.12-slim AS base
+
+WORKDIR /app
+
+COPY pyproject.toml .
+COPY src/ src/
+
+RUN pip install --no-cache-dir ".[api]"
+
+RUN useradd -r -u 1000 app
+USER app
+
+EXPOSE 8000
+
+CMD ["uvicorn", "claude_memory.api.app:app", "--host", "0.0.0.0", "--port", "8000"]