Add entity customer numbers and scope APIs via selected company.

Entity gets an optional unique-per-company number with allocate/peek/isNumberFree helpers. Company-scoped store methods no longer take companyId and resolve google_auth.selected_company instead.

API.unit.md

@@ -10,7 +10,7 @@ Deletes a unit for a company by its SI code.
 
 ```js
 const fn = del(pool);
-await fn(42, 1, 'l');
+await fn(42, 'l');
 ```
 
 ## `unit.list`
@@ -21,7 +21,7 @@ Lists the units available for a company.
 
 ```js
 const fn = list(pool);
-const units = await fn(42, 1);
+const units = await fn(42);
 // => [{ id, si, basesi, basesifactor, symbol, name }]
 ```
 
@@ -33,6 +33,6 @@ Creates or updates a unit for a company, keyed by its SI code.
 
 ```js
 const fn = upsert(pool);
-const unit = await fn(42, 1, { si: 'l', basesi: 'm3', basesifactor: 0.001, symbol: 'L', name: 'Liter' });
+const unit = await fn(42, { si: 'l', basesi: 'm3', basesifactor: 0.001, symbol: 'L', name: 'Liter' });
 // => { id, si, basesi, basesifactor, symbol, name }
 ```