Add comments explaining why fabricspark and vertica are excluded from all extra

Co-Authored-By: Itamar Hartstein <haritamar@gmail.com>

Author: devin-ai-integration[bot]

pyproject.toml

@@ -76,6 +76,9 @@ fabric = ["dbt-fabric"]
 fabricspark = ["dbt-fabricspark"]
 sqlserver = ["dbt-sqlserver"]
 vertica = ["dbt-vertica"]
+# dbt-fabricspark is excluded due to broken upstream dependencies (azure-cli pre-release pins).
+# dbt-vertica is excluded because it pins dbt-core==1.8.5, forcing the entire resolution to dbt 1.8.
+# Both are still available as individual extras (e.g. pip install elementary-data[vertica]).
 all = ["dbt-snowflake", "dbt-bigquery", "dbt-redshift", "dbt-postgres", "dbt-databricks", "dbt-spark", "dbt-athena-community", "dbt-trino", "dbt-clickhouse", "dbt-duckdb", "dbt-dremio", "dbt-fabric", "dbt-sqlserver"]
 
 [build-system]