refactor: simplify redundant expressions in display and workspace_selector (#11)

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

Pass database= to client.execute_sql() so queries are scoped to a
managed database via the X-Database-Id header (hotdata-runtime>=0.2.1).
- HotdataMarimoEngine: add default_database= constructor param, pass to execute()
- SqlEditor: add database= constructor param, pass to both execute_sql calls
- ManagedDatabaseWriter: use description= kwarg matching ManagedDatabase v0.2.0 API
- Fix test_databases_marimo.py syntax error and update assertions

* refactor: eliminate flag-based side-effect tracking, fix unregister, remove dead code

- table_browser: extract _set_table_pick() replacing duplicate _init/_rebuild methods;
  _sync_table_catalog returns bool so ui drops _rebuilt_table_pick_this_run flag;
  standardize _active_connection_id to use 'or None' consistently
- sql_engine: unregister now restores original engine_to_data_source_connection and
  resets sentinel so register/unregister/register round-trip works correctly
- sql_editor: remove dead 'or ""' on _cached_sql (already guarded by None check above)
- workspace_selector: cache HotdataClient, only reconstruct when workspace_id changes

* fix: pass dropdown label key (not value) to mo.ui.dropdown value= init param

When options is a dict {label: value}, Marimo validates value= against the
dict keys (labels), not the values. _rebuild_database_pick was passing a
database ID (dict value) which raised ValueError on startup. Now resolves
the label key corresponding to the previously-selected ID instead.

* docs: rewrite README with quickstart and usage examples

* chore: remove publish-workflow.sh scaffold (workflow already generated)

* refactor: simplify redundant expressions in display and workspace_selector

---------

Co-authored-by: Eddie A Tejeda <669988+eddietejeda@users.noreply.github.com>

Author: eddietejeda

hotdata_marimo/display.py

@@ -90,14 +90,13 @@ def selected_result_id(self) -> str | None:
         row = selected[0]
         if not isinstance(row, dict):
             return None
-        rid = row.get("result_id")
-        return rid if rid else None
+        return row.get("result_id") or None
 
     @property
     def result(self) -> QueryResult:
         rid = self.selected_result_id
         mo.stop(rid is None, mo.md("Select a result row to load."))
-        return self._client.get_result(rid or "")
+        return self._client.get_result(rid)
 
     @property
     def result_panel(self):

hotdata_marimo/workspace_selector.py

@@ -62,7 +62,7 @@ def workspace_id(self) -> str:
         if self._pick is None:
             return self._workspace_id
         v = self._pick.value
-        return v if v else self._workspace_id
+        return v or self._workspace_id
 
     @property
     def client(self) -> HotdataClient: