OData and REST grids in CodeGenNew

Shape of the templates

• The OData page is the same template run with Variant=OData (TSX_Page, TSX_DetailMasterPage, TS_Component, TS_DetailMasterComponent, BLZ_Page). A grid feature is one edit with an if (odata) branch, never a copy of the template. Update the template header comment and Docs/TemplateNotes/<Name>_v1.md for each of the five.
• Essentials (PagedCrudScreen, ODataPagedScreen) are written once and kept, so older projects hold the old file. Put new behavior in the page template or in a plan template (database-level, rewritten every run). Example: Angular GridColumns keeps sortable and properties as arrays updated in place and the screen hands them over once, so no essentials file changed.
• Shared support code (components/gridColumns.tsx, grid-columns.ts, Services/GridColumns.cs) is a DatabaseOnly template per stack; a rule all three must agree on lives in Core (ChosenGridColumns: Offered, Initial, Sortable, Resolve, Toggle, CutLength) with one test that reads the lists each stack wrote for the same table and compares them with the rule.

Behavior rules to keep

• Hiding a column drops a sort on it and a filter typed for it. REST re-reads without the sort (clearSort() / sortBy = null); OData filters the sorts, resets the filters of the hidden field and re-reads.
• OData builds $select from the shown columns at every read. Edit reads the whole row by its key, so a hidden key or column never reaches the form.
• The last shown column cannot be cleared; a saved name the table no longer has is dropped; a stored value that is not a list is ignored; the key and credential columns are never offered.
• The choice is per browser and grid: localStorage gridColumns:<gridKey> (React, Angular), <project>.columns.<pageclass> (Blazor). Name/active lists get no picker.
• REST sorts by every column except long text and binary; REST grids have no filter row; the form already reads every parent list, so a foreign key shown late needs no extra call. Check such assumptions against the code before building from an item's text: the item 118 text was wrong on three of them.

Owner scope and roles

• On a table scoped to its owner, OData applies the scope whatever $select asks for; the REST search is refused with /problems/search-not-scoped; a REST read answers whole rows for one's own record and refuses another person's.
• Docs/Verification/Test-ODataScoping.js (39 checks, three real sign-ins on a scratch copy) is the proof. Add a check there for any change that widens what a request can ask for.

Proving a grid change

1. Unit suite (Core rule test, same-lists test, the template tests that assert the generated text).
2. Scratch copy of each sample with OData=true (React: npx tsc -b + vitest; Angular: ng build + ng test; Blazor: both projects build) and the API on a scratch database; see verify-in-running-app.
3. Click through on a wide table (Customer, 31 columns): tick and clear a column, hide the sorted column (next request has no sort), type a filter then hide its column (next request has none), read $select from the network request, reload (choice kept), store a bad value (ignored), press Edit (whole row).
4. Angular: Docs/Verification/Test-AngularVersion.ps1 -Version 18 (Karma/Jasmine) as well as the current version; generated specs may use only describe, it, expect, beforeEach. AdaptAngularHtml turns *ngIf into @if for Angular 21+, so tests assert both forms.
5. Switch the fix off once (remove clearSort()), see the generated test fail, restore.

Template traps seen here

• A #> inside a T4 string ends the block: build it from pieces.
• An import used only by generated tests (fireEvent) must be conditional on the same flag that writes the tests; helper definitions must be declared before first use.
• Blazor OData keeps the last Search's conditions while paging, so hiding a column re-reads the filter boxes and applies text typed but not yet searched; React and Angular apply typed text at every read. Report such differences instead of hiding them.
• Blazor does not render name/active lists; WinUI3 grids read the database directly and have no OData or Columns list.