fix(backend): #84 real woo_reachable, #83 reject unknown fields, #82 live taxonomy in stale_field, #80 persist review overrides

#84: /api/health woo_reachable is now a real check (GET /wp-json/ with a
3s timeout) instead of a hardcoded False stub. Version bumped to 0.5.0-m3-s1.

#83: POST /slabs rejects unknown (non-ALLOWED_FIELDS) keys with a 400
'unknown fields' error, instead of silently dropping them. The INSERT
binding count is now provably correct (no more assert needed).

#82: stale_field 422 error now returns the LIVE taxonomy ids
(SELECT id FROM table) as current_options, plus the field name and
submitted value, instead of echoing the submitted value back.

#80: regular review (no lock) persists owner overrides (price/sku/title/
short_description) from the payload to the DB via an UPDATE, so the
review endpoint is self-contained. server_rev is incremented on persist.

Tests: +3 (test_create_rejects_unknown_fields,
test_update_stale_field_returns_live_options,
test_review_persists_owner_overrides). 87/87 passing.

backend/app.py

@@ -25,7 +25,7 @@ from starlette.middleware.base import BaseHTTPMiddleware
 from .db import get_connection, init_db, probe_images_writable, probe_writable
 from . import settings as settings_mod
 
-__version__ = "0.5.0-m3-s0"
+__version__ = "0.5.0-m3-s1"
 
 # --- Structured JSON logging (stdlib only) ---
 request_id_var: ContextVar[str] = ContextVar("request_id", default="")
@@ -155,16 +155,33 @@ def _error(code: str, message: str, detail: Any = None) -> dict:
 
 @app.get("/api/health")
 async def health() -> dict[str, Any]:
-    """Health per APP-30/45: non-200 when db or image volume not writable (probe file)."""
+    """Health per APP-30/45: non-200 when db or image volume not writable (probe file).
+    #84: woo_reachable is a real check (HEAD /wp-json/ with a short timeout),
+    not a hardcoded stub.
+    """
     db_ok = probe_writable()
     img_ok = probe_images_writable()
     if not (db_ok and img_ok):
         logger.warning("health: storage not writable", extra={"request_id": request_id_var.get("")})
         raise HTTPException(status_code=503, detail="storage not writable")
+    woo_reachable = False
+    try:
+        woo_base = os.environ.get("WOO_BASE_URL", "")
+        if woo_base:
+            import urllib.request
+            req = urllib.request.Request(
+                woo_base.rstrip("/") + "/wp-json/",
+                method="GET",
+                headers={"User-Agent": "SlabUploader/health"},
+            )
+            with urllib.request.urlopen(req, timeout=3) as resp:
+                woo_reachable = resp.status < 500
+    except Exception:
+        woo_reachable = False
     return {
         "status": "ok",
         "version": __version__,
-        "woo_reachable": False,  # S0 stub; S4 will implement real check
+        "woo_reachable": woo_reachable,
     }