Align store calls with selected-company scoping and add entity numbers.

Drop companyId from company-scoped store wrappers and routes, add GET /entity/next-number plus optional number on entity create/update, and document dashdbschema API.md lookup in sibling-repos.

docs/api/routes/entity/create.md

@@ -5,6 +5,7 @@ Protected. Requires a valid session cookie (`credentials: 'include'`).
 Create entity
 
 Creates an entity in a company customer group and writes `entityhistory` (`Erstellt`).
+Optional `number`: omit to allocate the next customer number (`type` entity).
 
 
 ## Body (JSON)
@@ -13,7 +14,8 @@ Creates an entity in a company customer group and writes `entityhistory` (`Erste
 {
   "customergroupId": 1,
   "name": "Müller",
-  "firstName": "Anna"
+  "firstName": "Anna",
+  "number": "10042"
 }
 ```
 
@@ -28,6 +30,7 @@ Created entity
     "customergroupId": 1,
     "firstName": "…",
     "name": "…",
+    "number": "…",
     "createdAt": "2026-08-10T00:00:00.000Z",
     "updatedAt": "2026-08-10T00:00:00.000Z"
   }
@@ -38,10 +41,11 @@ Created entity
 
 | Status | Description |
 |--------|-------------|
-| 400 | Name required or no company selected — `{"error":"…"}` |
+| 400 | Name/number required or no company selected — `{"error":"…"}` |
 | 401 | Unauthorized — `{"error":"…"}` |
 | 403 | Not authorized — `{"error":"…"}` |
 | 404 | Company or customer group not found — `{"error":"…"}` |
+| 409 | Number already in use — `{"error":"…"}` |
 
 ---