Add POS terminal category visibility system

Add posterminal and posterminalcategory tables to control which categories
are visible on each POS terminal. The existence of a row in
posterminalcategory means the category is visible on that terminal.

Store methods:
- posterminal.list/upsert/delete - CRUD for terminals
- posterminal.setOn/setOff - toggle single category on a terminal
- posterminal.setOnAll/setOffAll - toggle all categories on a terminal
- posterminal.getCategoryPosterminalIds - internal, used by category tree

The category tree (getTreeForCompany) now includes a posterminalIds array
on each node listing which terminals have that category enabled.

src/schema.js

@@ -568,6 +568,34 @@ BEGIN
 END
 `;
 
+export const INIT_POSTERMINAL = `
+IF NOT EXISTS (SELECT * FROM sys.tables WHERE name = 'posterminal')
+BEGIN
+    CREATE TABLE posterminal (
+        id INT IDENTITY(1,1) PRIMARY KEY,
+        company_id INT NOT NULL,
+        token NVARCHAR(255) NULL,
+        pairingpin NVARCHAR(50) NOT NULL,
+        CONSTRAINT FK_posterminal_company FOREIGN KEY (company_id) REFERENCES company(id) ON DELETE CASCADE,
+        CONSTRAINT UQ_posterminal_token UNIQUE (token)
+    );
+END
+`;
+
+export const INIT_POSTERMINALCATEGORY = `
+IF NOT EXISTS (SELECT * FROM sys.tables WHERE name = 'posterminalcategory')
+BEGIN
+    CREATE TABLE posterminalcategory (
+        id INT IDENTITY(1,1) PRIMARY KEY,
+        posterminal_id INT NOT NULL,
+        category_id INT NOT NULL,
+        CONSTRAINT FK_posterminalcategory_posterminal FOREIGN KEY (posterminal_id) REFERENCES posterminal(id) ON DELETE CASCADE,
+        CONSTRAINT FK_posterminalcategory_category FOREIGN KEY (category_id) REFERENCES category(id) ON DELETE NO ACTION,
+        CONSTRAINT UQ_posterminalcategory_posterminal_category UNIQUE (posterminal_id, category_id)
+    );
+END
+`;
+
 /** DDL scripts in dependency order for schema init. */
 export const SCHEMA_SCRIPTS = [
   INIT_META,
@@ -604,4 +632,6 @@ export const SCHEMA_SCRIPTS = [
   INIT_COMPANYUSER,
   INIT_SYNCPOS,
   INIT_COMPANYSETTING,
+  INIT_POSTERMINAL,
+  INIT_POSTERMINALCATEGORY,
 ];