feat: make record avatar/icon resolution data-driven via a configurable image identifier field (#22644)

## Summary

Today the avatar/icon shown for a record is hardcoded per object —
Company pulls a favicon from its domain link, Person uses `avatarUrl`,
etc. This PR replaces that hardcoding with a generic, data-driven
abstraction based on a configurable **image identifier field** on each
object's metadata (mirroring the existing **label identifier** concept).

An object's image identifier can point to:
- a **`FILES`** field → the uploaded image is used directly (rounded
avatar), or
- a **`LINKS`** field → a favicon is derived from the primary URL via
the Twenty icons service (squared avatar), gated by
`ALLOW_REQUESTS_TO_TWENTY_ICONS`.

This lets any object type (Opportunity, a custom "Listing", etc.) define
its own avatar/icon without code changes, and makes the field
configurable/overridable for standard objects.


## ❓ Open question: also allow `TEXT` → direct image URL?
Right now the image identifier is restricted to `FILES` (uploaded file)
and `LINKS` (favicon). We deliberately left out `TEXT` → **direct image
URL** (e.g. an imported/synced photo URL stored in a text field).
There's precedent for it — Person's avatar was originally a `TEXT`
`avatarUrl`, and WorkspaceMember still is — and it's unambiguous (a
`TEXT` field has no favicon-vs-image ambiguity, and selecting it as the
image identifier is itself the declaration of intent). It's a small,
clean extension:
- add `TEXT` to the allowed image-identifier types,
- add an explicit `TEXT → raw URL` case
- `getAvatarType`: `TEXT → rounded`.
Caveats: it relies on admin assertion that the text values are image
URLs (no data-level guarantee), and external image URLs load third-party
content in the browser (IP-leak/hotlinking, same as favicons — a
proxy/cache would be the more robust long-term answer).

### ✅ Resolution
Decision: **we will not support `TEXT` as an image identifier.** Image
identifiers stay restricted to `FILES` and `LINKS`, and any other type
fails closed (returns no avatar) on both the frontend and backend.
Instead, the legacy items that still rely on a `TEXT` avatar — Person's
deprecated `avatarUrl` and WorkspaceMember's `avatarUrl` — will be
migrated to `FILE` fields in a follow-up PR. Until then, WorkspaceMember
remains an exception (its `avatarUrl` still resolves through the
existing CorePicture path), and legacy Person `avatarUrl` values that
haven't been migrated will show initials placeholders.


<!-- This is an auto-generated description by cubic. -->
<a
href="https://cubic.dev/pr/twentyhq/twenty/pull/22644?utm_source=github"
target="_blank" rel="noopener noreferrer"
data-no-image-dialog="true"><picture><source
media="(prefers-color-scheme: dark)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"><source
media="(prefers-color-scheme: light)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-light.svg"><img
alt="Review in cubic"
src="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"></picture></a>
<!-- End of auto-generated description by cubic. -->

packages/twenty-server/src/utils/image.ts

@@ -1,5 +1,8 @@
+import { detectPdf } from '@file-type/pdf';
 import { type AxiosInstance } from 'axios';
 import { isNonEmptyString } from '@sniptt/guards';
+import { FileTypeParser } from 'file-type';
+import { isDefined } from 'twenty-shared/utils';
 
 export const getImageBufferFromUrl = async (
   url: string,
@@ -44,3 +47,19 @@ export const getImageBufferFromUrl = async (
     throw new Error(`Failed to fetch image from ${url}: ${message}`);
   }
 };
+
+export const fetchImageWithTypeFromUrl = async (
+  imageUrl: string,
+  axiosInstance: AxiosInstance,
+): Promise<{ buffer: Buffer; extension: string } | undefined> => {
+  const buffer = await getImageBufferFromUrl(imageUrl, axiosInstance);
+
+  const parser = new FileTypeParser({ customDetectors: [detectPdf] });
+  const type = await parser.fromBuffer(buffer);
+
+  if (!isDefined(type) || !type.mime.startsWith('image/')) {
+    return undefined;
+  }
+
+  return { buffer, extension: type.ext };
+};