feat: add color property to ObjectMetadata for object icon customization (#18672)

## Summary

- Adds a `color` column to `ObjectMetadataEntity` with full GraphQL
support so object icon colors are persisted at the metadata level
- Adds a `type` column to `NavigationMenuItemEntity` (enum: `OBJECT`,
`VIEW`, `FOLDER`, `LINK`, `RECORD`) replacing field-based type inference
- Updates frontend to read object colors from `objectMetadata.color`
(falling back to standard defaults) in the sidebar nav, record index
header, and record show breadcrumb
- Simplifies `NavigationMenuItemIcon` color resolution via
`getEffectiveNavigationMenuItemColor` util

## Color rules

| Item type | Color source | Editable in sidebar? |
|-----------|-------------|---------------------|
| **Object** | `objectMetadata.color` | Yes — persisted to
`objectMetadata.color` on Save |
| **Folder** | `navigationMenuItem.color` | Yes |
| **Link** | Fixed default (`DEFAULT_NAVIGATION_MENU_ITEM_COLOR_LINK`) |
No |
| **View** | `objectMetadata.color` (from the parent object) | No |
| **Record** | None | No |

- **Object** items represent the whole object (e.g. "Companies") and
point to the INDEX view. Changing their color updates
`objectMetadata.color` via `useSaveObjectMetadataColorsFromDraft`.
- **View** items represent specific non-INDEX views. Their color comes
from the parent object's metadata (read-only).
- Only **folders** store their color on `navigationMenuItem.color` —
enforced by `hasNavigationMenuItemOwnColor` util.
- `getEffectiveNavigationMenuItemColor` returns `objectColor` for both
OBJECT and VIEW items, folder's own color for folders, and the fixed
default for links.

## NavigationMenuItemType enum

- Shared enum created in `twenty-shared` with values: `OBJECT`, `VIEW`,
`FOLDER`, `LINK`, `RECORD`
- Registered as a GraphQL enum on the backend
- Replaces string literals across entity, DTOs, input, converters, and
frontend hooks
- Migration backfills existing rows: INDEX views → `OBJECT`, non-INDEX
views → `VIEW`, based on join with the view table

## Design decisions

- **OBJECT vs VIEW distinction**: Items pointing to INDEX views are
typed as `OBJECT` (represent the whole object, color editable). Items
pointing to non-INDEX views are typed as `VIEW` (specific view, color
read-only from parent object).
- **Dual color storage**: `navigationMenuItem.color` is preserved for
folders only. Objects use `objectMetadata.color` as their source of
truth.
- **Type discriminator**: The `type` column replaces field-based
inference (checking `viewId`, `link`, `targetRecordId` presence) with an
explicit enum, simplifying `isNavigationMenuItemLink` /
`isNavigationMenuItemFolder` to simple `item.type ===` checks.
- **No settings page color picker**: Object color editing is done from
the sidebar edit panel, not the data model settings page.

## Test plan

- [ ] Verify objects display their default standard colors in the
sidebar
- [ ] Verify object color editing works in the sidebar edit panel
(persists to objectMetadata.color)
- [ ] Verify folder color editing works in the sidebar edit panel
- [ ] Verify views, links, and records do NOT show a color picker in the
sidebar edit panel
- [ ] Run `npx nx typecheck twenty-front` and `npx nx typecheck
twenty-server`
- [ ] Verify the database migrations add `color` to `objectMetadata` and
`type` to `navigationMenuItem`


Made with [Cursor](https://cursor.com)

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/__tests__/__snapshots__/all-universal-flat-entity-properties-to-compare-and-stringify.constant.spec.ts.snap

@@ -105,6 +105,7 @@ exports[`ALL_UNIVERSAL_FLAT_ENTITY_PROPERTIES_TO_COMPARE_AND_STRINGIFY should ma
   },
   "navigationMenuItem": {
     "propertiesToCompare": [
+      "type",
       "position",
       "folderUniversalIdentifier",
       "name",
@@ -116,6 +117,7 @@ exports[`ALL_UNIVERSAL_FLAT_ENTITY_PROPERTIES_TO_COMPARE_AND_STRINGIFY should ma
   },
   "objectMetadata": {
     "propertiesToCompare": [
+      "color",
       "description",
       "icon",
       "isActive",

packages/twenty-server/src/engine/metadata-modules/flat-entity/constant/all-entity-properties-configuration-by-metadata-name.constant.ts

@@ -149,6 +149,11 @@ export const ALL_ENTITY_PROPERTIES_CONFIGURATION_BY_METADATA_NAME = {
       toStringify: false,
       universalProperty: undefined,
     },
+    color: {
+      toCompare: true,
+      toStringify: false,
+      universalProperty: undefined,
+    },
     description: {
       toCompare: true,
       toStringify: false,
@@ -1070,6 +1075,11 @@ export const ALL_ENTITY_PROPERTIES_CONFIGURATION_BY_METADATA_NAME = {
     },
   },
   navigationMenuItem: {
+    type: {
+      toCompare: true,
+      toStringify: false,
+      universalProperty: undefined,
+    },
     position: {
       toCompare: true,
       toStringify: false,

packages/twenty-server/src/engine/metadata-modules/flat-entity/types/__tests__/flat-entity-update.type-test.ts

@@ -38,6 +38,7 @@ type Assertions = [
     Equal<
       keyof FlatEntityUpdate<'objectMetadata'>,
       | 'icon'
+      | 'color'
       | 'description'
       | 'isActive'
       | 'standardOverrides'