feat: componente SearchBar con debounce y clear

Input de busqueda con icono, debounce configurable y boton de limpiar.
Exportado desde index.ts del barrel de UI.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/functions/ui/index.ts

@@ -114,6 +114,10 @@ export type { TextareaProps } from './textarea'
 export { Toast, ToastProvider, ToastViewport, toastVariants, useToast } from './toast'
 export type { ToastEntry, ToastProps, ToastViewportProps } from './toast'
 
+// Search
+export { SearchBar } from './search_bar'
+export type { SearchBarProps } from './search_bar'
+
 // Hooks — Canvas
 export { useAnimatedCanvas } from './use_animated_canvas'
 

frontend/functions/ui/search_bar.md

@@ -0,0 +1,64 @@
+---
+name: search_bar
+kind: component
+lang: ts
+domain: ui
+version: "1.0.0"
+purity: impure
+signature: "SearchBar(props: SearchBarProps): JSX.Element"
+description: "Search input with debounce, search icon, and clear button"
+tags: [component, ui, search, input, debounce]
+uses_functions: [cn_ts_core]
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: ["lucide-react"]
+tested: false
+tests: []
+test_file_path: ""
+file_path: "frontend/functions/ui/search_bar.tsx"
+props:
+  - name: onSearch
+    type: "(query: string) => void"
+    required: true
+    description: "Called with the debounced search query"
+  - name: placeholder
+    type: "string"
+    required: false
+    description: "Placeholder text (default: Search...)"
+  - name: debounceMs
+    type: "number"
+    required: false
+    description: "Debounce delay in ms (default: 300)"
+  - name: className
+    type: "string"
+    required: false
+    description: "Additional CSS classes"
+emits: []
+has_state: true
+framework: react
+variant: []
+---
+
+## Ejemplo
+
+```tsx
+import { SearchBar } from '@fn_library'
+
+function MyPage() {
+  return (
+    <SearchBar
+      onSearch={(query) => console.log('search:', query)}
+      placeholder="Search entities..."
+      debounceMs={300}
+    />
+  )
+}
+```
+
+## Notas
+
+- Debounce usa ref para evitar re-renders innecesarios del callback
+- El icono de clear solo aparece cuando hay texto
+- Usa CSS variables del tema para colores (border, input, foreground, muted-foreground)

frontend/functions/ui/search_bar.tsx

@@ -0,0 +1,65 @@
+import * as React from "react"
+import { cn } from "../core/cn"
+import { Search, X } from "lucide-react"
+
+interface SearchBarProps {
+  /** Called with the debounced search query */
+  onSearch: (query: string) => void
+  /** Placeholder text */
+  placeholder?: string
+  /** Debounce delay in ms (default 300) */
+  debounceMs?: number
+  /** Additional CSS classes for the outer wrapper */
+  className?: string
+}
+
+function SearchBar({
+  onSearch,
+  placeholder = "Search...",
+  debounceMs = 300,
+  className,
+}: SearchBarProps) {
+  const [query, setQuery] = React.useState("")
+  const timerRef = React.useRef<ReturnType<typeof setTimeout> | null>(null)
+  const onSearchRef = React.useRef(onSearch)
+  onSearchRef.current = onSearch
+
+  React.useEffect(() => {
+    if (timerRef.current) clearTimeout(timerRef.current)
+    timerRef.current = setTimeout(() => {
+      onSearchRef.current(query)
+    }, debounceMs)
+    return () => {
+      if (timerRef.current) clearTimeout(timerRef.current)
+    }
+  }, [query, debounceMs])
+
+  return (
+    <div
+      className={cn(
+        "flex flex-1 items-center gap-2 rounded border border-border bg-input px-2 py-1",
+        className,
+      )}
+    >
+      <Search size={14} className="text-muted-foreground shrink-0" />
+      <input
+        value={query}
+        onChange={(e) => setQuery(e.target.value)}
+        placeholder={placeholder}
+        className="flex-1 bg-transparent text-sm text-foreground outline-none placeholder:text-muted-foreground"
+      />
+      {query && (
+        <button
+          onClick={() => setQuery("")}
+          className="p-0.5 text-muted-foreground hover:text-foreground"
+          aria-label="Clear search"
+        >
+          <X size={12} />
+        </button>
+      )}
+    </div>
+  )
+}
+
+export { SearchBar }
+export type { SearchBarProps }