feat: add 4 built-in gradients, searchable gradient picker, cleaner modal titles

- Add warm, cool, neon, pastel built-in gradients (promoted from frontend presets)
- Change gradient seeding to add missing built-ins on every startup (not just first run)
- Add searchable option to IconSelect component for filtering by name
- Enable search on gradient, effect palette, and audio palette pickers
- Simplify modal titles: "Add Gradient" / "Edit Gradient" instead of "Add Color Strip Source: Gradient"
- Update INSTALLATION.md and .env.example

server/src/wled_controller/storage/gradient_store.py

@@ -1,8 +1,8 @@
 """Gradient storage with built-in seeding.
 
-Provides CRUD for gradient entities.  On first run (empty/missing data),
-seeds 8 built-in gradients matching the legacy hardcoded palettes.
-Built-in gradients are read-only and cannot be deleted or modified.
+Provides CRUD for gradient entities.  On startup, seeds any missing
+built-in gradients.  Built-in gradients are read-only and cannot be
+deleted or modified.
 """
 
 import uuid
@@ -36,6 +36,16 @@ _BUILTIN_DEFS = {
         (0.75, 255, 192, 64), (1.0, 255, 255, 192),
     ],
     "ice": [(0, 0, 0, 64), (0.33, 0, 64, 192), (0.66, 128, 192, 255), (1.0, 240, 248, 255)],
+    "warm": [(0, 255, 255, 80), (0.33, 255, 160, 0), (0.67, 255, 60, 0), (1.0, 160, 0, 0)],
+    "cool": [(0, 0, 255, 200), (0.33, 0, 120, 255), (0.67, 60, 0, 255), (1.0, 120, 0, 180)],
+    "neon": [
+        (0, 255, 0, 200), (0.25, 0, 255, 255), (0.5, 0, 255, 50),
+        (0.75, 255, 255, 0), (1.0, 255, 0, 100),
+    ],
+    "pastel": [
+        (0, 255, 180, 180), (0.2, 255, 220, 160), (0.4, 255, 255, 180),
+        (0.6, 180, 255, 200), (0.8, 180, 200, 255), (1.0, 220, 180, 255),
+    ],
 }
 
 
@@ -50,14 +60,16 @@ class GradientStore(BaseSqliteStore[Gradient]):
 
     def __init__(self, db: Database):
         super().__init__(db, Gradient.from_dict)
-        if not self._items:
-            self._seed_builtins()
+        self._seed_missing_builtins()
 
-    def _seed_builtins(self) -> None:
-        """Create the 8 built-in gradients on first run."""
+    def _seed_missing_builtins(self) -> None:
+        """Seed any built-in gradients not yet in the store."""
         now = datetime.now(timezone.utc)
+        added = 0
         for name, tuples in _BUILTIN_DEFS.items():
             gid = f"gr_builtin_{name}"
+            if gid in self._items:
+                continue
             gradient = Gradient(
                 id=gid,
                 name=name.capitalize(),
@@ -69,7 +81,9 @@ class GradientStore(BaseSqliteStore[Gradient]):
             )
             self._items[gid] = gradient
             self._save_item(gid, gradient)
-        logger.info(f"Seeded {len(_BUILTIN_DEFS)} built-in gradients")
+            added += 1
+        if added:
+            logger.info(f"Seeded {added} new built-in gradients")
 
     # Aliases
     get_all_gradients = BaseSqliteStore.get_all