feat: add database= parameter to sql engine and editor for managed database scoping

[eddietejeda]

Summary

• Adds default_database: str | None = None to HotdataMarimoEngine.__init__, passed to execute_sql() so mo.sql queries are scoped to a managed database via X-Database-Id header
• Adds database: str | None = None to SqlEditor.__init__ and sql_editor() factory, passed to both execute_sql calls (run and rerun paths)
• Updates ManagedDatabaseWriter to use description= kwarg for create_managed_database (matches ManagedDatabase API from hotdata-runtime v0.2.0)
• Bumps hotdata-runtime dependency to >=0.2.1 to pick up the database= support and X-Database-Id header fix
• Fixes test_databases_marimo.py syntax error from corrupted duplicate function and updates create_managed_database assertion to use description= kwarg

[claude]

nit: (not blocking) two subtleties here worth a quick check:

1. Dropdown value semantics changed from name to id. Previously database.value was the database name; now it's the id. That id is then passed positionally to load_managed_table(database, ...) in _maybe_load (line 189). Worth double-checking that hotdata-runtime 0.2.1's load_managed_table accepts the id as the first arg (vs. the old name) — test_managed_database_writer_loads_parquet still asserts load_managed_table.assert_called_once_with("sales", ...) and only passes because the dropdown is mocked, so it doesn't actually validate the new behavior.

2. Description collisions silently collapse. Two managed databases with the same description (or both unset, falling back to db.id which is unique — that case is fine) collapse to a single dropdown entry because dict keys must be unique. Probably rare, but consider disambiguating, e.g. {(db.description or db.id) if uniq else f"{db.description} ({db.id})": db.id for ...} or just including the id in the label unconditionally.