v0.7.0rc3 — soak-substrate (test trio + coverage gate)

[0.7.0rc3] - 2026-05-22

Test coverage

• CI now enforces ≥80% test coverage. pyproject.toml gains
  [tool.coverage.run] + [tool.coverage.report] config with
  fail_under = 80; ci.yml runs pytest --cov so a PR that drops
  coverage below the floor fails the build. Excluded modules
  (dashboard/*, __main__.py, upgrade.py, downgrade.py,
  llm.py) are under-testable-by-design and documented in the
  config — Streamlit UI / entry-point shim / release-engineering
  scripts requiring real Fly+AWS / deprecated optional-LLM module
  the deployed product doesn't use.
• Current coverage: 86% (suite 850 → 855 passing).
• README coverage badge added: coverage-86%-brightgreen.
  Static, manually updated on each release (matches the existing
  static-badge pattern for Status / Python / License / MCP).
• New tests/test_nli.py additions cover: _ensure_loaded HF
  download failure → NLIUnavailableError; _ensure_loaded
  unexpected label-set rejection; prewarm() swallows
  unavailability per acceptable-secondary-observability category;
  classify_pair softmax + input-building path with stubbed session.

CI / release tooling

• New .github/workflows/ci-server-extras.yml workflow. Installs
  mnemon-memory[server] ONLY (the production-equivalent install
  used by the Fly Docker image) plus pytest as a separate test
  runner, and runs the full suite under that minimal install. Catches
  the failure class that bit memory_check_contradictions on
  2026-05-22 — production code that imports something from [llm] /
  [ui] would pass ci.yml (full [dev] extras installed) but
  fail this workflow. Includes a guard assertion that
  llama-cpp-python is NOT installed under [server] — so a future
  PR can't accidentally move it across without flipping the
  intentional "mnemon is LLM-free by default" posture.

• scripts/promote_stable.sh layer3 --exercise-all-tools. New
  opt-in flag that, after the test Fly app is up but before the
  downgrade step, iterates every registered MCP tool against the
  remote and asserts each returns cleanly (no opaque error envelope,
  no unhandled exception, no NLI/embedder/baked-model breakage).
  Composes with tests/test_tools_integration.py (PR #158, local-
  process Python-level canary): this Fly-level probe catches the
  failure modes the local canary can't see (missing baked models,
  Anthropic MCP proxy timeouts, transport regressions). Tool list
  resolved dynamically from mcp._tool_manager._tools so tools
  added in future PRs are exercised automatically. Adds ~30-60s to
  the layer3 run; opt-in so non-NLI-touching releases aren't taxed.

• scripts/_layer3_remote_helper.py gains an exercise-all-tools
  subcommand wired through the FastMCP tool manager. Two regression-
  lock tests added to tests/test_promote_stable.sh harness (15
  passing, was 13) covering helper dispatch + flag plumbing through
  the bash dispatcher.