refactor(gui): clean up flagged issues before merge

1. Make migration 015 idempotent with IF NOT EXISTS

2. Remove hardcoded cadence range from routes.py and template:
   - Added ge=10 constraint to AdapterConfig.cadence_s field
   - Removed manual 60-3600 check from routes.py POST handler
   - Validate cadence using AdapterConfig field metadata
   - Removed min/max attributes from template input

3. Move discover_adapters to its own module:
   - Created src/central/adapter_discovery.py
   - Updated supervisor.py to import from adapter_discovery
   - Updated routes.py to import from adapter_discovery
   - GUI no longer transitively imports nats or stream_manager

4. Remove dead code branch in form_descriptors.py:
   - Removed unreachable RegionConfig check (already handled earlier)
   - Improved error message for unsupported nested types

5. Updated test_adapters.py:
   - Changed invalid cadence test from 30 to 5 (below ge=10)
   - Updated assertion to check for "10" in error message

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sql/migrations/015_add_adapters_last_error.sql

@@ -3,4 +3,4 @@
 -- Populated by supervisor when an adapter fails to start or apply config.
 
 ALTER TABLE config.adapters
-ADD COLUMN last_error TEXT;
+ADD COLUMN IF NOT EXISTS last_error TEXT;

src/central/adapter_discovery.py

@@ -0,0 +1,34 @@
+"""Adapter discovery utilities."""
+
+import importlib
+import logging
+import pkgutil
+
+import central.adapters
+from central.adapter import SourceAdapter
+
+logger = logging.getLogger(__name__)
+
+
+def discover_adapters() -> dict[str, type[SourceAdapter]]:
+    """Auto-discover adapter classes from central.adapters package."""
+    registry: dict[str, type[SourceAdapter]] = {}
+    for module_info in pkgutil.iter_modules(central.adapters.__path__):
+        try:
+            module = importlib.import_module(f"central.adapters.{module_info.name}")
+        except Exception as e:
+            logger.error(
+                "Failed to import adapter module",
+                extra={"module": module_info.name, "error": str(e)},
+            )
+            continue
+        for attr_name in dir(module):
+            attr = getattr(module, attr_name)
+            if (
+                isinstance(attr, type)
+                and issubclass(attr, SourceAdapter)
+                and attr is not SourceAdapter
+                and hasattr(attr, "name")
+            ):
+                registry[attr.name] = attr
+    return registry

src/central/config_models.py

@@ -32,7 +32,7 @@ class AdapterConfig(BaseModel):
 
     name: str = Field(description="Unique adapter identifier")
     enabled: bool = Field(default=True, description="Whether adapter is active")
-    cadence_s: int = Field(description="Poll interval in seconds")
+    cadence_s: int = Field(ge=10, description="Poll interval in seconds")
     settings: dict[str, Any] = Field(
         default_factory=dict, description="Adapter-specific settings"
     )

src/central/gui/form_descriptors.py

@@ -59,12 +59,12 @@ def _type_to_widget(field_name: str, field_type: type) -> str:
             f"Field '{field_name}' has unsupported list type: list[{args[0].__name__ if args else '?'}]"
         )
 
-    # Check if it's a BaseModel subclass (nested model)
+    # Check if it's a BaseModel subclass (nested model other than RegionConfig)
     if isinstance(field_type, type) and issubclass(field_type, BaseModel):
-        if field_type is RegionConfig:
-            return "region"
         raise NotImplementedError(
-            f"Field '{field_name}' has unsupported nested type: {field_type.__name__}"
+            f"Field '{field_name}' has unsupported nested type: {field_type.__name__}. "
+            f"If a second nested type beyond RegionConfig is needed, "
+            f"refactor describe_fields to recurse over nested models."
         )
 
     raise NotImplementedError(

src/central/gui/routes.py

@@ -48,7 +48,7 @@ from functools import cache
 
 from central.gui.db import get_pool
 from central.gui.form_descriptors import describe_fields, FieldDescriptor
-from central.supervisor import discover_adapters
+from central.adapter_discovery import discover_adapters
 from pydantic import ValidationError
 
 @cache
@@ -1384,11 +1384,13 @@ async def adapters_edit_submit(
         "cadence_s": cadence_s_str,
     }
 
-    # Validate cadence_s
+    # Validate cadence_s using AdapterConfig field constraint (ge=10)
     try:
         cadence_s = int(cadence_s_str)
-        if cadence_s < 60 or cadence_s > 3600:
-            errors["cadence_s"] = "Cadence must be between 60 and 3600 seconds"
+        from central.config_models import AdapterConfig
+        min_cadence = AdapterConfig.model_fields["cadence_s"].metadata[0].ge
+        if cadence_s < min_cadence:
+            errors["cadence_s"] = f"Input should be greater than or equal to {min_cadence}"
     except ValueError:
         errors["cadence_s"] = "Cadence must be a valid integer"
         cadence_s = 0

src/central/gui/templates/adapters_edit.html

@@ -39,7 +39,7 @@
         <label for="cadence_s">Cadence (seconds)</label>
         <input type="number" id="cadence_s" name="cadence_s"
                value="{{ form_data.cadence_s if form_data else adapter.cadence_s }}"
-               min="60" max="3600" required>
+               required>
         {% if errors and errors.cadence_s %}
         <small style="color: var(--pico-color-red-500);">{{ errors.cadence_s }}</small>
         {% endif %}

src/central/supervisor.py

@@ -13,41 +13,14 @@ from typing import Any
 import nats
 from nats.js import JetStreamContext
 
-import importlib
-import pkgutil
-
 from central.adapter import SourceAdapter
+from central.adapter_discovery import discover_adapters
 from central.cloudevents_wire import wrap_event
 from central.config_models import AdapterConfig
 from central.config_source import ConfigSource, DbConfigSource
 from central.config_store import ConfigStore
 from central.bootstrap_config import get_settings
 from central.stream_manager import StreamManager
-import central.adapters
-
-def discover_adapters() -> dict[str, type[SourceAdapter]]:
-    """Auto-discover adapter classes from central.adapters package."""
-    registry: dict[str, type[SourceAdapter]] = {}
-    for module_info in pkgutil.iter_modules(central.adapters.__path__):
-        try:
-            module = importlib.import_module(f"central.adapters.{module_info.name}")
-        except Exception as e:
-            logger.error(
-                "Failed to import adapter module",
-                extra={"module": module_info.name, "error": str(e)},
-            )
-            continue
-        for attr_name in dir(module):
-            attr = getattr(module, attr_name)
-            if (
-                isinstance(attr, type)
-                and issubclass(attr, SourceAdapter)
-                and attr is not SourceAdapter
-                and hasattr(attr, "name")
-            ):
-                registry[attr.name] = attr
-    return registry
-
 CURSOR_DB_PATH = Path("/var/lib/central/cursors.db")
 
 # Stream subject mappings

tests/test_adapters.py

@@ -189,7 +189,7 @@ class TestAdaptersEditSubmit:
 
     @pytest.mark.asyncio
     async def test_adapters_edit_invalid_cadence_shows_error(self):
-        """POST /adapters/nws with cadence_s=30 shows error, no DB update."""
+        """POST /adapters/nws with cadence_s=5 shows error, no DB update."""
         from central.gui.routes import adapters_edit_submit
 
         mock_request = MagicMock()
@@ -199,7 +199,7 @@ class TestAdaptersEditSubmit:
         mock_form = MagicMock()
         mock_form.get.side_effect = lambda k, d="": {
             "csrf_token": "test_csrf_token",
-            "cadence_s": "30",
+            "cadence_s": "5",
             "contact_email": "test@example.com",
             "region_north": "49.0",
             "region_south": "24.0",
@@ -241,7 +241,7 @@ class TestAdaptersEditSubmit:
         call_args = mock_templates.TemplateResponse.call_args
         context = call_args.kwargs.get("context", call_args[1].get("context"))
         assert "cadence_s" in context["errors"]
-        assert "60" in context["errors"]["cadence_s"] or "3600" in context["errors"]["cadence_s"]
+        assert "10" in context["errors"]["cadence_s"]
 
 
 class TestAdaptersAudit: