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-front/src/testing/mock-data/generated/metadata/objects/mock-objects-metadata.ts

@@ -8638,7 +8638,7 @@ export const mockedStandardObjectMetadataQueryResult: ObjectMetadataItemsQuery =
               "__typename": "Field",
               "id": "15cffcf2-ed38-4ee1-956a-d8bc9d2bef16",
               "universalIdentifier": "20202020-4aa0-4ae8-898d-7df0afd47ab1",
-              "type": "RICH_TEXT_V2",
+              "type": "RICH_TEXT",
               "name": "bodyV2",
               "label": "Body",
               "description": "Task body",
@@ -23733,7 +23733,7 @@ export const mockedStandardObjectMetadataQueryResult: ObjectMetadataItemsQuery =
               "__typename": "Field",
               "id": "71961f86-5386-4cc9-b23a-39fc5c1c7c5e",
               "universalIdentifier": "20202020-a7bb-4d94-be51-8f25181502c8",
-              "type": "RICH_TEXT_V2",
+              "type": "RICH_TEXT",
               "name": "bodyV2",
               "label": "Body",
               "description": "Note body",