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/database/commands/upgrade-version-command/2-15/2-15-instance-command-fast-1781900000000-add-view-kanban-column-width.ts

@@ -0,0 +1,21 @@
+import { QueryRunner } from 'typeorm';
+
+import { RegisteredInstanceCommand } from 'src/engine/core-modules/upgrade/decorators/registered-instance-command.decorator';
+import { FastInstanceCommand } from 'src/engine/core-modules/upgrade/interfaces/fast-instance-command.interface';
+
+@RegisteredInstanceCommand('2.15.0', 1781900000000)
+export class AddViewKanbanColumnWidthFastInstanceCommand
+  implements FastInstanceCommand
+{
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "core"."view" ADD COLUMN IF NOT EXISTS "kanbanColumnWidth" integer`,
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "core"."view" DROP COLUMN IF EXISTS "kanbanColumnWidth"`,
+    );
+  }
+}

packages/twenty-server/src/database/commands/upgrade-version-command/2-15/add-view-kanban-column-width-upgrade-command-name.constant.ts

@@ -0,0 +1,2 @@
+export const ADD_VIEW_KANBAN_COLUMN_WIDTH_UPGRADE_COMMAND_NAME =
+  '2.15.0_AddViewKanbanColumnWidthFastInstanceCommand_1781900000000';

packages/twenty-server/src/database/commands/upgrade-version-command/instance-commands.constant.ts

@@ -74,6 +74,7 @@ import { EncryptNonSecretApplicationVariableSlowInstanceCommand } from 'src/data
 import { MigrateAiModelPreferencesSlowInstanceCommand } from 'src/database/commands/upgrade-version-command/2-9/2-9-instance-command-slow-1799000010000-migrate-ai-model-preferences';
 import { AddHasPaymentMethodToBillingCustomerFastInstanceCommand } from 'src/database/commands/upgrade-version-command/2-15/2-15-instance-command-fast-1781280240009-add-has-payment-method-to-billing-customer';
 import { AddFolderImportToMessageFolderPendingSyncActionFastInstanceCommand } from './2-15/2-15-instance-command-fast-1781714499016-add-folder-import-to-message-folder-pending-sync-action';
+import { AddViewKanbanColumnWidthFastInstanceCommand } from './2-15/2-15-instance-command-fast-1781900000000-add-view-kanban-column-width';
 
 export const INSTANCE_COMMANDS = [
   AddViewFieldGroupIdIndexOnViewFieldFastInstanceCommand,
@@ -150,4 +151,5 @@ export const INSTANCE_COMMANDS = [
   AddIsSystemSideEffectFastInstanceCommand,
   BackfillConnectionSecuritySlowInstanceCommand,
   AddFolderImportToMessageFolderPendingSyncActionFastInstanceCommand,
+  AddViewKanbanColumnWidthFastInstanceCommand,
 ];