feat(11-03): add TagMultiSelect component with hashed tag colors

- TAG_COLORS 7-color pastel palette + getTagColorIndex() deterministic
  name->color hash (D-07, no stored color column)
- renders tag badges with inline remove (X), calls removeTagFromService
- "+" dropdown to add a new tag via Enter, calls addTagToService
- closes dropdown on outside click and Escape; inline error display

src/components/ui/tag-multi-select.tsx

@@ -0,0 +1,162 @@
+"use client";
+
+import { useState, useRef, useEffect, useTransition } from "react";
+import { Badge } from "@/components/ui/badge";
+import { Input } from "@/components/ui/input";
+import { Button } from "@/components/ui/button";
+import { X, Plus } from "lucide-react";
+import { cn } from "@/lib/utils";
+import { addTagToService, removeTagFromService } from "@/app/admin/catalog/actions";
+
+// D-07: deterministic name -> color index, no stored `color` column.
+// 7-color pastel palette, bg-*-100/text-*-900 pairs for AA contrast on white.
+const TAG_COLORS = [
+  "bg-blue-100 text-blue-900",
+  "bg-green-100 text-green-900",
+  "bg-purple-100 text-purple-900",
+  "bg-pink-100 text-pink-900",
+  "bg-amber-100 text-amber-900",
+  "bg-teal-100 text-teal-900",
+  "bg-orange-100 text-orange-900",
+];
+
+export function getTagColorIndex(name: string): number {
+  let hash = 0;
+  for (let i = 0; i < name.length; i++) {
+    hash = (hash << 5) - hash + name.charCodeAt(i);
+    hash |= 0; // 32-bit int
+  }
+  return Math.abs(hash) % TAG_COLORS.length;
+}
+
+export interface TagMultiSelectProps {
+  tags: string[];
+  serviceId: string;
+  onTagsChanged?: () => void;
+}
+
+export function TagMultiSelect({ tags, serviceId, onTagsChanged }: TagMultiSelectProps) {
+  const [isOpen, setIsOpen] = useState(false);
+  const [newTag, setNewTag] = useState("");
+  const [isPending, startTransition] = useTransition();
+  const [error, setError] = useState<string | null>(null);
+  const inputRef = useRef<HTMLInputElement>(null);
+  const containerRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    function handleClickOutside(e: MouseEvent) {
+      if (containerRef.current && !containerRef.current.contains(e.target as Node)) {
+        setIsOpen(false);
+      }
+    }
+    document.addEventListener("mousedown", handleClickOutside);
+    return () => document.removeEventListener("mousedown", handleClickOutside);
+  }, []);
+
+  useEffect(() => {
+    if (isOpen && inputRef.current) {
+      inputRef.current.focus();
+    }
+  }, [isOpen]);
+
+  function handleAddTag() {
+    const trimmed = newTag.trim();
+    if (!trimmed) return;
+    setError(null);
+    startTransition(async () => {
+      try {
+        await addTagToService(serviceId, trimmed);
+        setNewTag("");
+        onTagsChanged?.();
+      } catch (e) {
+        setError(e instanceof Error ? e.message : "Errore nel salvataggio");
+      }
+    });
+  }
+
+  function handleRemoveTag(tagName: string) {
+    startTransition(async () => {
+      try {
+        await removeTagFromService(serviceId, tagName);
+        onTagsChanged?.();
+      } catch (e) {
+        setError(e instanceof Error ? e.message : "Errore nella rimozione");
+      }
+    });
+  }
+
+  return (
+    <div ref={containerRef} className="relative w-full min-w-[140px]">
+      <div
+        onClick={() => setIsOpen((v) => !v)}
+        className="flex flex-wrap gap-1 items-center px-2 py-1 rounded cursor-pointer hover:bg-[#f0f0f0] transition-colors duration-150 min-h-[28px]"
+      >
+        {tags.length === 0 ? (
+          <span className="text-xs text-[#71717a]">—</span>
+        ) : (
+          tags.map((tag) => (
+            <Badge
+              key={tag}
+              variant="outline"
+              className={cn(
+                TAG_COLORS[getTagColorIndex(tag)],
+                "border-transparent text-xs px-2 py-0.5 gap-1 font-medium"
+              )}
+            >
+              {tag}
+              <button
+                type="button"
+                onClick={(e) => {
+                  e.stopPropagation();
+                  handleRemoveTag(tag);
+                }}
+                disabled={isPending}
+                className="hover:opacity-70 disabled:opacity-30"
+                aria-label={`Rimuovi tag ${tag}`}
+              >
+                <X className="h-3 w-3" />
+              </button>
+            </Badge>
+          ))
+        )}
+        <Plus className="h-3.5 w-3.5 text-[#71717a]" />
+      </div>
+
+      {isOpen && (
+        <div className="absolute top-full left-0 mt-1 bg-white border border-[#e5e7eb] rounded-md shadow-md p-2 z-10 min-w-[200px]">
+          <div className="flex gap-1">
+            <Input
+              ref={inputRef}
+              type="text"
+              placeholder="Nome tag..."
+              value={newTag}
+              onChange={(e) => setNewTag(e.target.value)}
+              onKeyDown={(e) => {
+                if (e.key === "Enter") {
+                  e.preventDefault();
+                  handleAddTag();
+                }
+                if (e.key === "Escape") {
+                  e.preventDefault();
+                  setIsOpen(false);
+                }
+              }}
+              className="text-sm h-8 ring-1 ring-primary"
+              disabled={isPending}
+            />
+            <Button
+              type="button"
+              size="sm"
+              onClick={handleAddTag}
+              disabled={isPending || !newTag.trim()}
+              className="bg-[#1A463C] text-white hover:bg-[#1A463C]/90 h-8 px-2"
+            >
+              +
+            </Button>
+          </div>
+          {error && <p className="text-xs text-red-600 mt-1">{error}</p>}
+        </div>
+      )}
+    </div>
+  );
+}