(core) Draft version of AI assistant

Summary:
The feature is behind a flag GRIST_FORMULA_ASSISTANT (must be "true"). But can be enabled in the
developer console by invoking GRIST_FORMULA_ASSISTANT.set(true).

Keys can be overriden in the document settings page.

Test Plan: For now just a stub test that checks if this feature is disabled by default.

Reviewers: paulfitz

Reviewed By: paulfitz

Subscribers: dsagal

Differential Revision: https://phab.getgrist.com/D3815

app/client/ui/FieldConfig.ts

@@ -3,6 +3,7 @@ import {CursorPos} from 'app/client/components/Cursor';
 import {GristDoc} from 'app/client/components/GristDoc';
 import {BEHAVIOR, ColumnRec} from 'app/client/models/entities/ColumnRec';
 import {buildHighlightedCode, cssCodeBlock} from 'app/client/ui/CodeHighlight';
+import {buildAiButton} from 'app/client/ui/FormulaAssistance';
 import {GristTooltips} from 'app/client/ui/GristTooltips';
 import {cssBlockedCursor, cssLabel, cssRow} from 'app/client/ui/RightPanelStyles';
 import {withInfoTooltip} from 'app/client/ui/tooltips';
@@ -12,6 +13,7 @@ import {testId, theme} from 'app/client/ui2018/cssVars';
 import {textInput} from 'app/client/ui2018/editableLabel';
 import {cssIconButton, icon} from 'app/client/ui2018/icons';
 import {IconName} from 'app/client/ui2018/IconList';
+import {GRIST_FORMULA_ASSISTANT} from 'app/client/models/features';
 import {selectMenu, selectOption, selectTitle} from 'app/client/ui2018/menus';
 import {createFormulaErrorObs, cssError} from 'app/client/widgets/FormulaEditor';
 import {sanitizeIdent} from 'app/common/gutil';
@@ -356,6 +358,7 @@ export function buildFormulaConfig(
         ]),
         formulaBuilder(onSaveConvertToFormula),
         cssEmptySeparator(),
+        dom.maybe(GRIST_FORMULA_ASSISTANT(), () => cssRow(buildAiButton(gristDoc, origColumn))),
         cssRow(textButton(
           t("Convert to trigger formula"),
           dom.on("click", convertFormulaToTrigger),