refactor: decouple adapter class-identity (kind) from instance-identity (name) (#120)

Adds a `kind` TEXT column to `config.adapters` (migration 043) so one adapter
class can later back many operator-created instances.  Every built-in adapter
row is back-filled with `kind = name`, keeping all 23 adapters working
unchanged.

- Migration 043: ADD COLUMN IF NOT EXISTS kind, back-fill, SET NOT NULL.
- AdapterConfig gains `kind: str | None` with a model_validator that falls
  back to `name` when the column is NULL/absent (pre-043 rows).
- config_store.get_adapter / list_adapters: add `kind` to SELECT.
- supervisor._create_adapter AND _start_adapter (api-key precondition):
  resolve the class by config.kind (class key) not config.name (instance key);
  runtime state keying stays on config.name.
- routes.py GET/POST /adapters/{name} and adapters_list: add `kind` to SELECT,
  resolve the adapter class by row["kind"].
- adapter_discovery.py: comment clarifying .name is the kind (class identity).
- Out of scope, left as-is (built-ins only, name==kind): setup wizard paths in
  routes.py (~750/~891/~1109) and gui/__init__.py.
- Tests: 17 new pure-unit tests (migration SQL shape, AdapterConfig back-compat,
  _create_adapter + _start_adapter kind dispatch). Existing test mock rows
  updated to include the `kind` field.

Co-authored-by: Ubuntu <zvx@cortex.echo6.co>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_gui_adapter_edit.py

@@ -116,7 +116,7 @@ def _post_req(pairs, cadence_s="1800"):
 def _pool(settings=_SETTINGS):
     conn = AsyncMock()
     conn.fetchrow.side_effect = [
-        {"name": "tomtom_incidents", "enabled": True, "cadence_s": 1800, "settings": settings,
+        {"name": "tomtom_incidents", "kind": "tomtom_incidents", "enabled": True, "cadence_s": 1800, "settings": settings,
          "paused_at": None, "updated_at": None, "last_error": None},
         {"map_tile_url": None, "map_attribution": None},
     ]