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/database/commands/upgrade-version-command/upgrade.command.ts

@@ -35,6 +35,7 @@ import { BackfillMissingStandardViewsCommand } from 'src/database/commands/upgra
 import { SeedServerIdCommand } from 'src/database/commands/upgrade-version-command/1-19/1-19-seed-server-id.command';
 import { BackfillCommandMenuItemsCommand } from 'src/database/commands/upgrade-version-command/1-20/1-20-backfill-command-menu-items.command';
 import { BackfillPageLayoutsCommand } from 'src/database/commands/upgrade-version-command/1-20/1-20-backfill-page-layouts.command';
+import { MigrateRichTextToTextCommand } from 'src/database/commands/upgrade-version-command/1-20/1-20-migrate-rich-text-to-text.command';
 import { TwentyConfigService } from 'src/engine/core-modules/twenty-config/twenty-config.service';
 import { WorkspaceEntity } from 'src/engine/core-modules/workspace/workspace.entity';
 import { DataSourceService } from 'src/engine/metadata-modules/data-source/data-source.service';
@@ -87,6 +88,7 @@ export class UpgradeCommand extends UpgradeCommandRunner {
     // 1.20 Commands
     protected readonly backfillCommandMenuItemsCommand: BackfillCommandMenuItemsCommand,
     protected readonly backfillPageLayoutsCommand: BackfillPageLayoutsCommand,
+    protected readonly migrateRichTextToTextCommand: MigrateRichTextToTextCommand,
   ) {
     super(
       workspaceRepository,
@@ -133,6 +135,7 @@ export class UpgradeCommand extends UpgradeCommandRunner {
     ];
 
     const commands_1200: VersionCommands = [
+      this.migrateRichTextToTextCommand,
       this.backfillCommandMenuItemsCommand,
       this.backfillPageLayoutsCommand,
     ];