feat: rename RICH_TEXT_V2 → RICH_TEXT in codebase (keep DB value) (#18628)

## Summary

- Renames the `FieldMetadataType` enum key from `RICH_TEXT_V2` to
`RICH_TEXT` across the entire codebase, while keeping the underlying
string value as `'RICH_TEXT_V2'` to maintain PostgreSQL database
compatibility
- Renames all related types, guards, hooks, components, and files from
`*RichTextV2*` / `*rich-text-v2*` to `*RichText*` / `*rich-text*` (e.g.
`FormRichTextV2FieldInput` → `FormRichTextFieldInput`,
`isFieldRichTextV2` → `isFieldRichText`)
- Updates generated files (GraphQL schema, SDK types) to use the new key
while preserving the `RICH_TEXT_V2` string value for DB/API layer
- Updates i18n locale files, test snapshots, and integration tests to
reflect the rename

## Context

The legacy `RICH_TEXT` (V1) field type was deprecated and migrated to
`TEXT` in a previous PR (#18623). With V1 gone, the `RICH_TEXT_V2`
naming is no longer necessary — `RICH_TEXT` is now the canonical name.
The DB enum value stays `'RICH_TEXT_V2'` to avoid confusion with the
just-deprecated V1 type and to prevent a database migration.

## Test plan

- [x] `twenty-server` typecheck passes
- [x] `twenty-front` typecheck passes (only pre-existing Apollo client
errors remain)
- [x] `twenty-server` lint passes
- [x] `twenty-front` lint passes
- [x] `twenty-shared` build passes
- [ ] CI passes


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

packages/twenty-server/src/engine/metadata-modules/flat-field-metadata/utils/from-create-field-input-to-flat-field-metadatas-to-create.util.ts

@@ -183,7 +183,7 @@ export const fromCreateFieldInputToFlatFieldMetadatasToCreate = async ({
     case FieldMetadataType.POSITION:
     case FieldMetadataType.ADDRESS:
     case FieldMetadataType.RAW_JSON:
-    case FieldMetadataType.RICH_TEXT_V2:
+    case FieldMetadataType.RICH_TEXT:
     case FieldMetadataType.ACTOR:
     case FieldMetadataType.ARRAY: {
       const indexMetadatas: UniversalFlatIndexMetadata[] = [];