feat(adr-117/p5+p-tomb): pip-release workflow + v1.99.0 tombstone wheel

P5 — `.github/workflows/pip-release.yml`:
- cibuildwheel matrix per ADR §5.4: manylinux x86_64 + aarch64,
  macos x86_64 + arm64, win amd64 (5 wheels via abi3-py310 stable
  ABI — one binary per OS/arch covers Python 3.10–3.13)
- Linux aarch64 cross-builds via QEMU; rustup 1.82 pinned in
  CIBW_BEFORE_ALL_LINUX for reproducibility
- Per-wheel smoke test: import wifi_densepose, assert hello()=="ok"
- sdist via `maturin sdist`
- Trigger: workflow_dispatch + push to `v*-pip` tags ONLY (never
  on regular commits — won't accidentally publish)
- TestPyPI dry-run gate via `repository-url: https://test.pypi.org/legacy/`
- Production PyPI publish via Trusted Publisher OIDC (no API tokens
  in GH secrets per ADR §9). Requires one-time PyPI Trusted Publisher
  registration before the first publish can fire.
- Q3 (witness hash v2 — ADR-117 §11.3) flagged in workflow comments
  as a hard gate before the first tag.

P-tomb — `python/tombstone/`:
- Separate `wifi-densepose==1.99.0` sdist+wheel using setuptools
  backend (NOT maturin — tombstone is pure Python, no Rust).
- `src/wifi_densepose/__init__.py` raises ImportError with the
  migration URL on import. Verified locally: 2.7 KB wheel,
  `pip install` then `import wifi_densepose` raises ImportError
  with `pip install wifi-densepose==2.0.0` hint + repo URL.
- 5 unit tests (`tests/test_tombstone.py`) lock the file content
  down: must `raise ImportError`, must contain v2 install hint
  and migration URL, must NOT contain any `def`/`class`/`import`
  beyond the bare `raise` — so a well-intentioned refactor can't
  accidentally bloat the tombstone into a real module that loads
  partway before failing.

Both wheels are published by the same pip-release.yml workflow:
- `v1.99.0-pip` tag → publishes tombstone (or via workflow_dispatch
  with `target: v1-99-tombstone`)
- `v2.X.Y-pip` tag → publishes the v2 wheel matrix

Per ADR-117 §7.3: tag and publish 1.99.0-pip FIRST so the tombstone
claims the "current" slot in pip's resolver, THEN publish 2.0.0-pip.

Test count unchanged in main python/ suite (156/156). Tombstone
sub-suite: 5 passing.

Refs: docs/adr/ADR-117-pip-wifi-densepose-modernization.md §5.4, §7
Refs: #785

Co-Authored-By: claude-flow <ruv@ruv.net>

python/README.md

@@ -68,10 +68,23 @@ python/
   discovery payload parser), `SemanticPrimitiveListener` (typed router
   for the 10 HA-MIND primitives from ADR-115 §3.12). 63 tests including
   end-to-end against an in-process `websockets.serve` fixture.
-- ⏳ **P5 — cibuildwheel + PyPI publish**: Linux/macOS/Windows × abi3-py310.
-- ⏳ **P-tomb — v1.99.0 tombstone wheel**: pure-Python ImportError
-  with migration URL, published to PyPI to soft-fence v1.x users
-  before v2.0 ships.
+- ⏳ **P5 — cibuildwheel + PyPI publish (workflow shipped)**: GH Actions
+  workflow `.github/workflows/pip-release.yml` ships the 5-wheel
+  matrix (manylinux x86_64+aarch64, macosx x86_64+arm64, win amd64)
+  plus sdist via `cibuildwheel@2.21`. Publish via PyPI Trusted
+  Publisher (OIDC) on `v2.X.Y-pip` tags or manual dispatch.
+  **One-time PyPI Trusted Publisher registration required before the
+  first publish can fire.** Q3 (witness hash v2 — ADR-117 §11.3)
+  remains the hard gate before tagging.
+- ✅ **P-tomb — v1.99.0 tombstone wheel**: pure-Python wheel
+  (`python/tombstone/`) whose `wifi_densepose/__init__.py` raises
+  ImportError with the migration URL on import. Verified locally
+  (2.7 KB wheel) — `pip install wifi_densepose-1.99.0-py3-none-any.whl`
+  then `python -c "import wifi_densepose"` raises ImportError as
+  expected. Same `pip-release.yml` workflow publishes the tombstone
+  on `v1.99.0-pip` tag. Per ADR-117 §7.3, publish the tombstone
+  BEFORE the first v2.0.0 publish to claim the "current" slot in
+  pip's resolver.
 
 Each phase ends with a checkbox PR. Tests are additive — every phase's
 smoke tests must still pass after later phases land.