Add company-scoped unit list/upsert/delete and article unit patches.

Units are isolated per company; article detail exposes full unit shape, and unused units can be deleted safely via FK NO ACTION.

src/schema.js

@@ -163,10 +163,12 @@ IF NOT EXISTS (SELECT * FROM sys.tables WHERE name = 'unit')
 BEGIN
     CREATE TABLE unit (
         id INT IDENTITY(1,1) PRIMARY KEY,
+        company_id INT NOT NULL,
         si NVARCHAR(50) NOT NULL,
         basesi NVARCHAR(50) NOT NULL,
         basesifactor FLOAT NOT NULL,
-        CONSTRAINT UQ_unit_si UNIQUE (si)
+        CONSTRAINT UQ_unit_company_si UNIQUE (company_id, si),
+        CONSTRAINT FK_unit_company FOREIGN KEY (company_id) REFERENCES company(id) ON DELETE NO ACTION
     );
 END
 `;
@@ -233,7 +235,7 @@ BEGIN
         fathersort INT NOT NULL CONSTRAINT DF_article_fathersort DEFAULT 0,
         created_at DATETIME2 NOT NULL CONSTRAINT DF_article_created_at DEFAULT SYSUTCDATETIME(),
         updated_at DATETIME2 NOT NULL CONSTRAINT DF_article_updated_at DEFAULT SYSUTCDATETIME(),
-        CONSTRAINT FK_article_unit FOREIGN KEY (unit_id) REFERENCES unit(id) ON DELETE CASCADE,
+        CONSTRAINT FK_article_unit FOREIGN KEY (unit_id) REFERENCES unit(id) ON DELETE NO ACTION,
         CONSTRAINT FK_article_brand FOREIGN KEY (brand_id) REFERENCES brand(id) ON DELETE SET NULL,
         CONSTRAINT FK_article_articlelist FOREIGN KEY (articlelist_id) REFERENCES articlelist(id) ON DELETE SET NULL,
         CONSTRAINT FK_article_optionslist FOREIGN KEY (optionslist_id) REFERENCES optionslist(id) ON DELETE SET NULL,