Fix CI: exclude demo/visual specs, fix oil-card→oil-chip selectors

- Grep pattern now matches full filenames (demo-walkthrough, visual-check)
- Updated all test files to use .oil-chip (new OilReference class name)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/cypress/e2e/oil-reference.cy.js

@@ -1,32 +1,32 @@
 describe('Oil Reference Page', () => {
   beforeEach(() => {
     cy.visit('/oils')
-    cy.get('.oil-card, .oils-grid', { timeout: 10000 }).should('exist')
+    cy.get('.oil-chip, .oils-grid', { timeout: 10000 }).should('exist')
   })
 
   it('displays oil grid with items', () => {
     cy.contains('精油价目').should('be.visible')
-    cy.get('.oil-card').should('have.length.gte', 10)
+    cy.get('.oil-chip').should('have.length.gte', 10)
   })
 
   it('shows oil name and price on each chip', () => {
-    cy.get('.oil-card').first().should('contain', '¥')
+    cy.get('.oil-chip').first().should('contain', '¥')
   })
 
   it('filters oils by search', () => {
-    cy.get('.oil-card').then($chips => {
+    cy.get('.oil-chip').then($chips => {
       const initial = $chips.length
       cy.get('input[placeholder*="搜索精油"]').type('薰衣草')
       cy.wait(300)
-      cy.get('.oil-card').should('have.length.lt', initial)
+      cy.get('.oil-chip').should('have.length.lt', initial)
     })
   })
 
   it('toggles between bottle and drop price view', () => {
-    cy.get('.oil-card').first().invoke('text').then(textBefore => {
+    cy.get('.oil-chip').first().invoke('text').then(textBefore => {
       cy.contains('滴价').click()
       cy.wait(300)
-      cy.get('.oil-card').first().invoke('text').should('not.eq', textBefore)
+      cy.get('.oil-chip').first().invoke('text').should('not.eq', textBefore)
     })
   })
 })