feat(workflow): scaffold core workflowVersion entity + trigger cache (phase 0) (#21674)

## What

**Phase 0 (scaffold)** of migrating `workflowVersion` data to **core**.
Gated by `IS_WORKFLOW_VERSION_IN_CORE_ENABLED` with **no behavior
change** — nothing reads or writes the new core entity yet.

## Plan

`workflowVersion` becomes a thin **workspace shell** over a core entity
(the `dashboard`/`pageLayout` pattern), so navigation, the metadata
relations, and the record UI keep working while the heavy data
(`triggers`, `steps`) lives in core. Trigger dispatch will derive from
active core versions via a per-workspace cache, letting us **eliminate**
the denormalized `workflowAutomatedTrigger` object. `workflow` and
`workflowRun` stay as workspace objects.

Phases: **0 — scaffold (this PR)** → A — backfill + dual-write → B —
switch reads to core → C — drop the workspace `trigger`/`steps` columns
+ the `workflowAutomatedTrigger` object.

## Included
- **Core `WorkflowVersionEntity`** (`extends WorkspaceRelatedEntity`) —
stores version data, with triggers as an **array** (`triggers:
WorkflowTrigger[]`), a long-due shape change. Storage only: dispatch
reads the primary trigger, so behavior stays single-trigger for now.
- **Fast create-table instance command** for `core."workflowVersion"`
(v2.19.0).
- **`IS_WORKFLOW_VERSION_IN_CORE_ENABLED`** feature flag.
- **Per-workspace automated-trigger cache provider** deriving
CRON/DATABASE_EVENT dispatch from the active version's trigger —
groundwork for removing `workflowAutomatedTrigger`.

## Notes
- `WorkspaceRelatedEntity`, **not** `SyncableEntity`: this is user
runtime data (like `connectedAccount`/`apiKey`/`file`), not
application-manifest metadata.
- No frontend behavior; the generated `FeatureFlagKey` enums are updated
to include the new flag.

packages/twenty-server/src/engine/twenty-orm/entity-manager/workspace-entity-manager.spec.ts

@@ -242,6 +242,7 @@ describe('WorkspaceEntityManager', () => {
         IS_LOGIC_FUNCTION_PREBUILT_MODE_ENABLED: false,
         IS_SETTINGS_DISCOVERY_HERO_ENABLED: false,
         IS_MESSAGING_CALENDAR_WEBHOOK_ENABLED: false,
+        IS_WORKFLOW_VERSION_IN_CORE_ENABLED: false,
       },
       userWorkspaceRoleMap: {},
       apiKeyRoleMap: {},