feat(stage): add Formatted/Unformatted toggle to the staging page

- Mirrors the review page's toggle: getstagetable.sas now also webouts
  fmt_stagetable (SAS-formatted), selectFormattedRows() picks between it
  and the raw stagetable, falling back to raw if fmt data is absent
- Adds stage.cy.ts e2e coverage and wires it into both build.yaml and
  release.yaml's cypress --spec lists (previously out of sync with
  each other on viewbox.cy.ts too)

client/cypress/e2e/stage.cy.ts

@@ -0,0 +1,61 @@
+const hostUrl = Cypress.env('hosturl')
+const appLocation = Cypress.env('appLocation')
+const longerCommandTimeout = Cypress.env('longerCommandTimeout')
+
+context('stage tests: ', function () {
+  this.beforeAll(() => {
+    cy.visit(`${hostUrl}/SASLogon/logout`)
+    cy.loginAndUpdateValidKey()
+  })
+
+  this.beforeEach(() => {
+    cy.visit(hostUrl + appLocation)
+
+    visitPage('stage/DC20221007T122326121_612316_7259')
+  })
+
+  // getstagetable's mock ignores the table_id param entirely, so any id in
+  // the URL resolves to the same fixture row - no need to submit a real
+  // table first just to reach this page.
+  it('1 | Formatted/Unformatted toggle switches between fmt_stagetable and stagetable, defaulting to formatted', () => {
+    cy.get('.app-loading', { timeout: longerCommandTimeout }).should(
+      'not.exist'
+    )
+
+    getCellByHeaderAndRow(0, 'SOME_DATE').should('have.text', '12FEB1960')
+
+    cy.get('.formatted-values-toggle').click()
+
+    getCellByHeaderAndRow(0, 'SOME_DATE').should('have.text', '42')
+
+    // Toggling back reverts to the formatted view.
+    cy.get('.formatted-values-toggle').click()
+
+    getCellByHeaderAndRow(0, 'SOME_DATE').should('have.text', '12FEB1960')
+  })
+})
+
+const visitPage = (url: string) => {
+  cy.visit(`${hostUrl}${appLocation}/#/${url}`)
+}
+
+// Locates a body cell by its column's header text rather than a hardcoded
+// childNodes index - same helper as editor.cy.ts's own.
+const getCellByHeaderAndRow = (rowIndex: number, headerText: string) => {
+  return cy
+    .get('.ht_clone_top .htCore thead tr th')
+    .should(($ths) => {
+      const texts = [...$ths].map((th) => th.innerText.trim())
+      expect(texts).to.include(headerText)
+    })
+    .then(($ths) => {
+      const index = [...$ths].findIndex(
+        (th) => th.innerText.trim() === headerText
+      )
+
+      return cy
+        .get('.ht_master tbody tr')
+        .then((rows: any) => rows[rowIndex].childNodes[index])
+        .then((cell) => cy.get(cell))
+    })
+}