feat: add resizable kanban column width (#21828)

## What & why

Lets users resize the columns of a Kanban (record board) view. Requested
by a user; the design avoids the "ragged board" problem by making the
width a **single shared value**.

## Behaviour

- A drag handle appears on the right edge of every column header.
- Because all columns read **one** width value, dragging any handle
resizes **every** column together — they can never end up mismatched.
- Width is clamped between **150px** and **400px** (default **200px**).
- The width is **persisted per view** and restored on reload.

## Approach

**Backend** — a new nullable `View.kanbanColumnWidth` field, threaded
through the existing view-level setting pattern (the same one
`kanbanAggregateOperation` / `shouldHideEmptyGroups` use), so it gets
create/update/manifest/override support for free:
- entity column + `ViewOverrides` + `@WasIntroducedInUpgrade`
- `CreateViewInput` / `UpdateViewInput` (`Int`, `@Min(150)`/`@Max(400)`)
+ `ViewDTO`
- flat-view editable properties, entity-properties config, compare-type,
standard-view + manifest converters
- a fast instance command adding the `core.view` column

**Frontend** — the value hydrates into a view-scoped atom and drives a
single CSS variable set on the board container, which both column
headers and bodies read. Live dragging only writes that CSS variable (no
per-move React re-render); the final width is committed to the atom and
persisted via `updateView` on pointer-up.

## Nullability / defaults

`kanbanColumnWidth` is nullable — `null` means "never resized" and the
UI falls back to the 200px default, so existing rows need no backfill.

## Validation

- `nx typecheck twenty-server` ✅ and `nx typecheck twenty-front` ✅
- `nx lint:diff-with-main twenty-server` ✅; frontend lint fixes applied
(split constants to one-per-file, removed `useRef`-for-state in favour
of `useState`).
- Draft pending a final green CI run (the dev container reclaimed
`node_modules` mid-session; re-running locally).

## Test plan

- [ ] Drag a kanban column edge → all columns resize together, clamped
150–400px
- [ ] Reload → width persists for that view; other views unaffected
- [ ] A view that was never resized still renders at 200px

https://claude.ai/code/session_016Qe6oDBkhVbrq2QkXBJ5nE

---
_Generated by [Claude
Code](https://claude.ai/code/session_016Qe6oDBkhVbrq2QkXBJ5nE)_

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---------

Co-authored-by: Claude <noreply@anthropic.com>

packages/twenty-server/src/engine/metadata-modules/view/dtos/inputs/create-view.input.ts

@@ -1,13 +1,16 @@
-import { Field, HideField, InputType } from '@nestjs/graphql';
+import { Field, HideField, InputType, Int } from '@nestjs/graphql';
 
 import {
   IsBoolean,
   IsEnum,
+  IsInt,
   IsNotEmpty,
   IsNumber,
   IsOptional,
   IsString,
   IsUUID,
+  Max,
+  Min,
 } from 'class-validator';
 import {
   AggregateOperations,
@@ -20,6 +23,8 @@ import {
 
 import { UUIDScalarType } from 'src/engine/api/graphql/workspace-schema-builder/graphql-types/scalars';
 import { IsValidMetadataName } from 'src/engine/decorators/metadata/is-valid-metadata-name.decorator';
+import { KANBAN_COLUMN_MAX_WIDTH } from 'src/engine/metadata-modules/view/constants/kanban-column-max-width.constant';
+import { KANBAN_COLUMN_MIN_WIDTH } from 'src/engine/metadata-modules/view/constants/kanban-column-min-width.constant';
 
 @InputType()
 export class CreateViewInput {
@@ -66,6 +71,13 @@ export class CreateViewInput {
   @Field({ nullable: true, defaultValue: false })
   shouldHideEmptyGroups?: boolean;
 
+  @IsOptional()
+  @IsInt()
+  @Min(KANBAN_COLUMN_MIN_WIDTH)
+  @Max(KANBAN_COLUMN_MAX_WIDTH)
+  @Field(() => Int, { nullable: true })
+  kanbanColumnWidth?: number;
+
   @IsOptional()
   @IsEnum(ViewOpenRecordIn)
   @Field(() => ViewOpenRecordIn, {