feat: new value source types (HA entity, gradient map, strip extract) + UI fixes

New value source types:
- ha_entity: reads numeric values from HA entity state/attribute, normalizes
  via min/max range, applies EMA smoothing. EntitySelect for HA connection
  and entity selection with live entity list fetching.
- gradient_map: maps a float value source (0-1) through a gradient entity.
  EntitySelect for both input source and gradient with inline previews.
- css_extract: extracts single color by averaging LED range from a color
  strip source. EntitySelect for source selection.

Value source type picker:
- Filter tabs (All / Numeric / Color) above the icon grid
- showTypePicker extended with filterTabs + onFilterChange support

Palette selectors converted to EntitySelect:
- Effect palette, gradient preset, and audio palette selectors now use
  command-palette style EntitySelect with gradient strip previews

Tab indicator fixes:
- Icon now updates on tab switch (was passing no args to updateTabIndicator)
- Visible with any background effect active, not just Noise Field
- Noise Field is the default background effect for new users

Dashboard section collapse fix:
- Split header into clickable toggle (chevron+label) and non-clickable
  actions area — buttons no longer trigger collapse/expand

Discriminated union fix (422 errors):
- source_type/target_type now always included in update payloads for:
  CSS editor, LED target, HA light target, simple calibration,
  advanced calibration

server/tests/e2e/test_target_flow.py

@@ -5,18 +5,20 @@ create device -> create target -> list -> update -> delete target -> cleanup dev
 """
 
 
-
 class TestOutputTargetLifecycle:
     """A user wires up an output target to a device."""
 
     def _create_device(self, client) -> str:
         """Helper: create a mock device and return its ID."""
-        resp = client.post("/api/v1/devices", json={
-            "name": "Target Test Device",
-            "url": "mock://target-test",
-            "device_type": "mock",
-            "led_count": 60,
-        })
+        resp = client.post(
+            "/api/v1/devices",
+            json={
+                "name": "Target Test Device",
+                "url": "mock://target-test",
+                "device_type": "mock",
+                "led_count": 60,
+            },
+        )
         assert resp.status_code == 201
         return resp.json()["id"]
 
@@ -44,7 +46,7 @@ class TestOutputTargetLifecycle:
         assert target["name"] == "E2E Test Target"
         assert target["device_id"] == device_id
         assert target["target_type"] == "led"
-        assert target["fps"] == 30
+        assert target["fps"] == 30.0
         assert target["protocol"] == "ddp"
 
         # 3. List targets -- should contain the new target
@@ -62,12 +64,12 @@ class TestOutputTargetLifecycle:
         # 5. Update the target -- change name and fps
         resp = client.put(
             f"/api/v1/output-targets/{target_id}",
-            json={"name": "Updated Target", "fps": 60},
+            json={"target_type": "led", "name": "Updated Target", "fps": 60},
         )
         assert resp.status_code == 200
         updated = resp.json()
         assert updated["name"] == "Updated Target"
-        assert updated["fps"] == 60
+        assert updated["fps"] == 60.0
 
         # 6. Verify update via GET
         resp = client.get(f"/api/v1/output-targets/{target_id}")
@@ -90,11 +92,14 @@ class TestOutputTargetLifecycle:
         """Deleting a device that has a target should return 409."""
         device_id = self._create_device(client)
 
-        resp = client.post("/api/v1/output-targets", json={
-            "name": "Blocking Target",
-            "target_type": "led",
-            "device_id": device_id,
-        })
+        resp = client.post(
+            "/api/v1/output-targets",
+            json={
+                "name": "Blocking Target",
+                "target_type": "led",
+                "device_id": device_id,
+            },
+        )
         assert resp.status_code == 201
         target_id = resp.json()["id"]
 
@@ -111,11 +116,14 @@ class TestOutputTargetLifecycle:
 
     def test_create_target_with_invalid_device_returns_422(self, client):
         """Creating a target with a non-existent device_id returns 422."""
-        resp = client.post("/api/v1/output-targets", json={
-            "name": "Orphan Target",
-            "target_type": "led",
-            "device_id": "nonexistent_device",
-        })
+        resp = client.post(
+            "/api/v1/output-targets",
+            json={
+                "name": "Orphan Target",
+                "target_type": "led",
+                "device_id": "nonexistent_device",
+            },
+        )
         assert resp.status_code == 422
 
     def test_get_nonexistent_target_returns_404(self, client):