fix: address review — preview stamping, stale producer set, public doc

Three findings from the local review round:

- Record the warehouse write only for a DEPLOYED script job. The annotation is
  a deploy-time contract (`manual`, three segments, a configured warehouse)
  checked where write access to the path is also required; honouring it in a
  preview, hub or inline-flow body let `jobs:run` alone restamp any relation's
  last writer from a script that never touched it.
- Exclude the deploying script's own rows from the producer set. Read
  committed, they describe the version being replaced, so a script dropping its
  `// materialize` while adding a subscription counted itself as the producer
  that would wake it and committed a dormant edge. It could not be that
  producer anyway — the dispatcher skips self-loops.
- `AssetKind::Dbt`'s doc no longer claims dbt is the exclusive producer of a
  warehouse relation, on both the types and the parser enum.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

backend/windmill-api-scripts/src/scripts.rs

@@ -2441,7 +2441,8 @@ async fn create_script_internal<'c>(
                 )));
             }
             if let Some(dbt_owner) =
-                windmill_common::assets::sole_dbt_producer(&db, &w_id, relation).await?
+                windmill_common::assets::sole_dbt_producer(&db, &w_id, relation, &ns.path)
+                    .await?
             {
                 return Err(Error::BadRequest(format!(
                     "`{trigger_ref}` cannot be subscribed to: it is built by the dbt project at \