Owner directive: minimal docs, focused on shipping. After #550 collapsed
this repo to the React-super-layer, most of `docs/` either described
the local API (now gone, in `django-admin-rest-api`) or agent
governance (sole-agent mode now).

## Deleted (47 files)
- `docs/agents/` — agent governance, autonomy policy, decisions log, PR
  workflow, per-role subdirs. None of it applies in sole-agent mode.
- `docs/api-contract.md` — wire contract for `django-admin-rest-api`;
  belongs in that repo, not duplicated here.
- `docs/extensions.md` — extension API doc that was already marked
  "not yet implemented" + the wiring lives in the API repo.
- `docs/threat-model.md` — STRIDE threat model. SECURITY.md is the
  durable security document; per-endpoint threat surface is now an
  API-repo concern.
- `docs/data-layer.md` — frontend data-layer internals; SPA-only and
  the code is its own documentation.
- `docs/ux/` — UX principles / nav / responsive / a11y / PWA. Was the
  PM agent's internal doc — sole-agent mode has no PM agent.
- `docs/consumer/` — pilot requirements; internal-only.

## Kept
- `docs/screenshots/` (6 PNGs + README) — referenced from `README.md`
  for the PyPI landing page.
- `docs/README.md` — trimmed to a 1-paragraph pointer at the screenshots
  + the root docs.

## Cross-link rot fixed
- `README.md`: dropped the "see `docs/extensions.md`" ref (API-repo
  concern) and "Full wire contract: `docs/api-contract.md`" (the API
  repo owns it).
- `ARCHITECTURE.md`: dropped 3 references to deleted docs/ files
  (decisions log, M2M ADR pointer, `installation.md`).
- `SECURITY.md`: surgically removed every ref to `docs/agents/`,
  `docs/threat-model.md`, `tests/test_security.py` (deleted with the
  API in #550), and the now-obsolete CI-revisit prose. The §10
  cross-references now point at README + ARCHITECTURE + the API
  repo's SECURITY.

## Verification
- 42 SPA tests pass (unchanged from #550).
- No remaining dead `docs/*` references in any of the 4 surviving
  root `.md` files.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>