feat(12.2-02): add the datepicker field with server-side bounds and date list columns

- type: datepicker compiles the D-20 keys; format maps to displayFormat with WinterCMS's momentFormat table
- boot fails when the mode does not match the column's Go type (time.Time, lagoon.Date, lagoon.TimeOfDay)
- datepicker is a writable scalar field; minDate and maxDate are rechecked on save
- columns.yaml accepts type: date and type: time; Scanner/Valuer structs are columns, not relations
- conformance fixture carries date and datetime fields; README, forms and lists docs

admin/src/api/schema.d.ts

@@ -2893,15 +2893,26 @@ export interface components {
             comment?: string;
             context?: components["schemas"]["cabana.fieldContext"];
             default?: components["schemas"]["cabana.jsonScalar"];
+            displayFormat?: string;
             emptyOption?: string;
             /** @description FileTypes are the allowed lower-case extensions of a fileupload field. */
             fileTypes?: string[];
             /** @description Fill lists the fields of the same form the action writes back (D-07). */
             fill?: string[];
+            /** @description FirstDay is the first day of the week, 0 (Sunday) to 6. */
+            firstDay?: number;
+            /**
+             * @description Format is a datepicker's WinterCMS (PHP date) display format;
+             *     DisplayFormat is the same format in the SPA's moment-style tokens.
+             */
+            format?: string;
+            /** @description IgnoreTimezone keeps a datetime's wall-clock value with no conversion. */
+            ignoreTimezone?: boolean;
             imageHeight?: number;
             /** @description ImageWidth and ImageHeight are the preview size of an image upload. */
             imageWidth?: number;
             label?: string;
+            maxDate?: string;
             /** @description MaxFiles caps the number of files of an attachMany field. */
             maxFiles?: number;
             /** @description MaxFilesize is the largest accepted file in megabytes. */
@@ -2911,7 +2922,15 @@ export interface components {
              *     fileupload field.
              */
             mimeTypes?: string[];
-            /** @description Mode is the fileupload mode (image or file, default file). */
+            /**
+             * @description MinDate and MaxDate bound a datepicker's calendar date (YYYY-MM-DD),
+             *     checked again on save.
+             */
+            minDate?: string;
+            /**
+             * @description Mode is the fileupload mode (image or file, default file) or the
+             *     datepicker mode (date, datetime or time, default datetime).
+             */
             mode?: string;
             multiple?: boolean;
             name: string;
@@ -2937,11 +2956,15 @@ export interface components {
             tab?: string;
             /** @description ThumbOptions carries the preview thumbnail mode. */
             thumbOptions?: components["schemas"]["cabana.ThumbOptions"];
+            /** @description TwelveHour shows a 12-hour clock. */
+            twelveHour?: boolean;
             type: string;
             /** @description UseCaption lets the admin edit each file's title and description. */
             useCaption?: boolean;
             /** @description Widget is the custom-element tag of a `type: widget` field (D-06). */
             widget?: string;
+            /** @description YearRange is [n] (years either side of today) or [from, to]. */
+            yearRange?: number[];
         };
         "cabana.FormMessages": {
             create: components["schemas"]["cabana.MessageForms"];