feat(cli): add --no-build flag to state push for state-only updates (#21374)

## Summary

Adds a `--no-build` flag to `coder state push` that updates the
Terraform state directly without triggering a workspace build.

## Use Case

This enables state-only migrations, such as migrating Kubernetes
resources from deprecated types (e.g., `kubernetes_config_map`) to
versioned types (e.g., `kubernetes_config_map_v1`):

```bash
coder state pull my-workspace > state.json
terraform init
terraform state rm -state=state.json kubernetes_config_map.example
terraform import -state=state.json kubernetes_config_map_v1.example default/example
coder state push --no-build my-workspace state.json
```

## Changes

- Add `PUT /api/v2/workspacebuilds/{id}/state` endpoint to update state
without triggering a build
- Add `UpdateWorkspaceBuildState` SDK method
- Add `--no-build`/`-n` flag to `coder state push`
- Add confirmation prompt (can be skipped with `--yes`/`-y`) since this
is a potentially dangerous operation
- Add test for `--no-build` functionality

Fixes #21336

docs/reference/cli/state_push.md

@@ -18,3 +18,11 @@ coder state push [flags] <workspace> <file>
 | Type | <code>int</code> |
 
 Specify a workspace build to target by name. Defaults to latest.
+
+### -n, --no-build
+
+|      |                   |
+|------|-------------------|
+| Type | <code>bool</code> |
+
+Update the state without triggering a workspace build. Useful for state-only migrations.