Deprecate legacy RICH_TEXT field metadata type (#18623)

## Summary

- Removes the deprecated `RICH_TEXT` (V1) field metadata type from the
codebase entirely
- Adds a 1.20 upgrade command that migrates existing `RICH_TEXT` fields
to `TEXT` in `core.fieldMetadata`
- Cleans up ~70 files across `twenty-shared`, `twenty-server`,
`twenty-front`, `twenty-sdk`, and `twenty-zapier`

## Context

`RICH_TEXT` was a legacy field type that stored rich text as a single
`text` column. It was already **read-only** — writes threw errors
directing users to `RICH_TEXT_V2` instead. `RICH_TEXT_V2` is the current
approach: a composite type with `blocknote` (editor JSON) and `markdown`
subfields. Keeping the deprecated type added maintenance burden without
any value.

Since the underlying database column type for `RICH_TEXT` was already
`text` (same as `TEXT`), the migration only needs to update the metadata
— no data migration or column changes required.

## Changes

### Upgrade command (new)
- `1-20-migrate-rich-text-to-text.command.ts` — runs `UPDATE
core."fieldMetadata" SET "type" = 'TEXT' WHERE "type" = 'RICH_TEXT'` per
workspace, with cache invalidation

### Enum & shared types
- Removed `RICH_TEXT` from `FieldMetadataType` enum
- Removed from `FieldMetadataDefaultValueMapping`,
`isFieldMetadataTextKind`

### Server (~30 files)
- Removed from type mapper (scalar, filter, order-by), data processors,
input transformer, filter operators, zod schemas, column type mapping,
searchable fields, RLS matching, OpenAPI schema, fake value generators
- Removed from field creation flow and field metadata type validator
- Updated dev seeder Pet `bio` field to `TEXT`
- Cleaned up mocks, snapshots, integration tests

### Frontend (~25 files)
- Deleted: `RichTextFieldDisplay`, `isFieldRichText`,
`isFieldRichTextValue`, `useRichTextFieldDisplay`
- Removed from `FieldDisplay`, `usePersistField`, `isFieldValueEmpty`,
`isRecordMatchingFilter`, `generateEmptyFieldValue`,
`isFieldCellSupported`, spreadsheet import, workflow fake values
- Removed from settings types, field type configs, and field creation
exclusion list
- Updated tests, mocks, and stories

### SDK & Zapier
- Removed from generated GraphQL schema and TypeScript types
- Removed from Zapier `computeInputFields`

packages/twenty-server/src/engine/workspace-manager/workspace-migration/workspace-migration-runner/utils/is-text-column-type.util.ts

@@ -1,8 +1,11 @@
 import { FieldMetadataType } from 'twenty-shared/types';
+
+// 'RICH_TEXT' kept as a raw string for pre-upgrade workspaces that haven't
+// yet run the 1.20 migrate-rich-text-to-text command.
 export const isTextColumnType = (type: FieldMetadataType) => {
   return (
     type === FieldMetadataType.TEXT ||
-    type === FieldMetadataType.RICH_TEXT ||
-    type === FieldMetadataType.ARRAY
+    type === FieldMetadataType.ARRAY ||
+    (type as string) === 'RICH_TEXT'
   );
 };