refactor: unifier les constats d’inventaire (#78)

docs/validation-parity-checklist.md

@@ -151,9 +151,10 @@ attachment-transfer endpoint or `targetTenantId` request.
 - **Authoritative constraints**:
     - `version` and `lines` are required; version is non-negative.
     - Every line requires a unique non-blank ID, valid apartment `privateAreaId`, non-blank
-      designation, equipment kind, and non-negative integer quantity.
-    - A regulatory category is unique. Its equipment classification cannot change; present,
-      absent, and undeclared quantities must agree with presence.
+      designation, and non-negative integer quantity.
+    - A regulatory category is unique; present, absent, and undeclared quantities must agree with
+      presence. Its inventory line carries the only furniture observation in the condition report,
+      without a derived equipment zone.
 - **Angular mirror**: the same editable line constraints produce indexed errors such as
   `lines[0].quantity`; the first invalid control is focused and editing clears that line's server
   error. Save is disabled only for the active inventory request.