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-sdk/src/clients/generated/metadata/schema.graphql

@@ -374,7 +374,7 @@ enum FieldMetadataType {
   RATING
   RAW_JSON
   RELATION
-  RICH_TEXT_V2
+  RICH_TEXT
   SELECT
   TEXT
   TS_VECTOR
@@ -873,7 +873,7 @@ type RatioAggregateConfig {
   optionValue: String!
 }
 
-type RichTextV2Body {
+type RichTextBody {
   blocknote: String
   markdown: String
 }
@@ -990,7 +990,7 @@ enum WidgetConfigurationType {
 
 type StandaloneRichTextConfiguration {
   configurationType: WidgetConfigurationType!
-  body: RichTextV2Body!
+  body: RichTextBody!
 }
 
 type PieChartConfiguration {
@@ -1606,6 +1606,7 @@ enum FeatureFlagKey {
   IS_DATE_TIME_WHOLE_DAY_FILTER_ENABLED
   IS_NAVIGATION_MENU_ITEM_EDITING_ENABLED
   IS_DRAFT_EMAIL_ENABLED
+  IS_RICH_TEXT_V1_MIGRATED
 }
 
 type SSOIdentityProvider {