v0.4.0

This release ships everything required for the v1.0 cut: a signed,
multi-arch container image; a Helm chart and raw K8s manifests; an
explicit public API surface and deprecation policy; and the full
Phase 0–3 enterprise readiness work (auth, hardening, multi-tenancy
scaffold, GDPR scheduled deletion). It is also the first release cut
through the new release.yml + verify-versions + cosign pipeline —
so the version itself is partly a dress rehearsal for v1.0.

Added — v1.0 release readiness

• requirements.lock (pip-compile, hash-pinned, includes [web] extras)
  and Dockerfile install via --require-hashes against it.
• Base image pinned by digest (python@sha256:...) instead of tag in
  Dockerfile.
• docs/RELEASE_RUNBOOK.md — durable,
  version-agnostic procedure for cutting a release across PyPI, GHCR,
  and the MCP registry.
• docs/MIGRATION_0.X_TO_1.0.md —
  contract for what changes (and what doesn't) at the v1.0 cut.
• memograph.scripts.migrate_to_multitenant — helper that relocates a
  single-vault 0.x deploy under a 1.0 global root with --dry-run.
• Expanded memograph.__all__ to declare the 1.0 public Python surface
  (MemoryKernel, MemoryQuery, SearchOptions, MemoryNode,
  VaultGraph, VaultStorage, HybridRetriever, and the GAM types).
• helm lint + double helm template render job in CI to catch chart
  regressions before they reach Helm users.

Added — Phase 0–3 enterprise readiness

The work below makes MemoGraph deployable to multiple paying
tenants with full GDPR procedures, observability, and authentication
without leaving the alpha branch. None of these change the
single-tenant developer experience, but they unlock the SaaS path.

Authentication & web hardening (Phase 1)

• OIDC bearer-token auth with JWKS support — works with Auth0, Clerk,
  WorkOS, Keycloak, Azure AD, Okta, Google Workspace.
• Hashed-API-key auth (X-API-Key) for service-to-service callers.
• MEMOGRAPH_AUTH_PROVIDER=multi accepts either credential type.
• slowapi rate limiting (per-key + per-IP, configurable).
• Restrictive CORS (default-deny, allowlist via MEMOGRAPH_CORS_ORIGINS).
• Request-size cap middleware (default 1 MB).
• Versioned /api/v1/ prefix; old /api/ redirects.
• Separate /healthz (liveness) and /readyz (readiness).
• Structured JSON logging with request-id propagation.
• Path-traversal-safe VaultStorage.write with control-char and
  reserved-name rejection.
• Vault size soft + hard caps with graceful error responses.
• Schema-versioned cache files with migration on load.
• 16 OWASP-top-10-style security tests under tests/security/.
• OpenAPI snapshot test in CI to catch unintentional contract drift.

Observability & reliability (Phase 2)

• OpenTelemetry FastAPI/asyncio auto-instrumentation; OTLP export.
• Prometheus /metrics endpoint as fallback for OTLP-less ops.
• Manual spans on kernel.search, kernel.remember, swarm cycles.
• Concurrency audit doc + targeted stress tests for concurrent
  reads, writes, deletes.
• Versioned backup format with sha256 manifest + integrity check
  on restore.
• bandit + pip-audit security workflow on every PR.

Multi-tenancy (Phase 3)

• ADR 0001 documenting the kernel-per-tenant + LRU eviction model.
• TenantStorage orchestrator: per-tenant directory layout under
  <global_root>/<tenant_id>/, validated tenant ids, filesystem-level
  isolation enforced before disk hits.
• TenantRegistry: bounded LRU of warm MemoryKernel instances;
  cold tenants evict cleanly with cache flush + lock release.
• Admin REST routes for tenant lifecycle: create, list, get, usage,
  immediate-offboard.
• kernel_for_request FastAPI dependency wires the registry into
  every non-admin route; per-request kernel resolution from the
  authenticated user's org_id claim. Single-tenant deployments
  (MEMOGRAPH_TENANCY_ENABLED unset) continue to work unchanged.
• Audit log carries tenant_id automatically via the existing
  current_user ContextVar — no kernel changes required.
• End-to-end isolation test suite (tests/tenancy/test_isolation_e2e.py)
  gating the multi-tenant release: cross-tenant search empty,
  get-by-id 404, list only own-tenant, admin offboard leaves siblings
  byte-identical, orphan users 403, single-tenant smoke preserved.

GDPR scheduled deletion (Phase 3.7)

• POST /api/v1/admin/tenants/{id}/schedule-delete with
  configurable grace period (default 7 days) and operator reason.
• DELETE /api/v1/admin/tenants/{id}/schedule-delete cancels
  before the reaper fires.
• Tombstone schema (_tombstone.json, schema-versioned) marks
  tenants for deletion; refuses overwrite to prevent misclick
  resets.
• python -m memograph.scripts.run_reaper <global_root> sweeps
  expired tombstones, takes a final backup tarball under
  .tombstoned-exports/, then destroys. JSON Lines on stdout;
  --dry-run for safe audits.
• Tombstoned tenants return 410 Gone to non-admin requests
  via tenant_resolver; admin routes still serve so operators
  can inspect or cancel.
• 33 tests across tombstone primitives, admin routes, routing
  layer, and reaper sweep behaviors.
• docs/GDPR_RUNBOOK.md rewritten to document the scheduled
  flow as the preferred Art. 17 procedure.

Enterprise documentation set

• docs/INSTALL_ENTERPRISE.md — multi-tenant on-prem + SaaS install.
• docs/SSO_SETUP.md — provider-neutral OIDC walkthrough.
• docs/RBAC_GUIDE.md — roles and scope mapping.
• docs/GDPR_RUNBOOK.md — Art. 15 / 17 / 20 procedures.
• docs/BACKUP_RESTORE_RUNBOOK.md — versioned-backup operations.
• docs/OBSERVABILITY_GUIDE.md — OTLP/Prometheus dashboards.
• docs/COMPLIANCE_ROADMAP.md — SOC 2 / ISO 27001 plan.
• docs/HOSTING_GUIDE.md — four genuinely-free hosting paths
  (Oracle Free, Cloudflare Tunnel, GCP, GitHub-vault) with
  hardening checklist.
• docs/GOOGLE_WORKSPACE_SETUP.md — Workspace OIDC + Drive
  portability backup walkthrough.
• docs/adr/0001-tenancy-model.md, docs/adr/0002-storage-adapter-strategy.md
  — architectural decision records.

Quickstart experience

• memograph quickstart — materialises a 15-note interconnected
  sample vault (Python development knowledge), ingests it, runs
  three illustrative live queries, prints next-step pointers.
  Total time from pip install to "wow" under 60 seconds.
• 12 tests covering bundled-vault integrity (every note parses,
  minimum link count, salience in range), the materialise primitive
  (idempotent, refuses to clobber non-empty targets without
  --force), and the end-to-end run.

Tests

• 172+ tests passing across tests/security/, tests/contract/,
  tests/tenancy/, plus 12 quickstart tests. Whole-package mypy
  clean.