## Fix SDK first-run build failure when generated API client is missing
### Problem
When running `twenty app:dev` for the first time, the build pipeline
crashes because:
1. The esbuild front-component watcher tries to resolve
`twenty-sdk/generated`, but the generated API client doesn't exist yet —
it's only created later in the pipeline after syncing with the server.
2. The typecheck plugin (`tsc --noEmit`) runs as a blocking esbuild
`onStart` hook, so even with stub files, type errors on the empty client
classes (e.g. `Property 'query' does not exist on type 'CoreApiClient'`)
cause the build to fail before the real client can be generated.
This creates a chicken-and-egg problem: the watchers need the generated
client to build, but the client is generated after the watchers produce
their output.
### Solution
**1. Stub generated client on startup**
Added `ensureGeneratedClientStub` to `ClientService` that writes minimal
placeholder files (`CoreApiClient`, `MetadataApiClient`) into
`node_modules/twenty-sdk/generated/` if the directory doesn't already
exist. This is called in `DevModeOrchestrator.start()` before any
watchers are created, so the `twenty-sdk/generated` import always
resolves.
**2. Skip typecheck on first sync round**
Made the esbuild typecheck plugin accept a `shouldSkipTypecheck`
callback. The orchestrator starts with `skipTypecheck = true` and passes
`() => this.skipTypecheck` through the watcher chain. After the real API
client is generated, the flag is flipped to `false`, so subsequent
rebuilds enforce full type checking with the real generated types.
