feat(10-03): add SendQuoteModal component and assignQuoteToLead server action

- Created SendQuoteModal.tsx with two tabs: existing quote (paste token) and create new
- Existing quote tab: paste quote token and submit to link quote to lead
- New quote tab: button redirects to quote builder pre-filled with lead_id
- Added assignQuoteToLead server action to link quote and update lead status to proposal_sent
- Validates quote token existence before linking
- Revalidates lead detail page on successful assignment

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

src/components/admin/leads/SendQuoteModal.tsx

@@ -0,0 +1,129 @@
+"use client";
+
+import { useState } from "react";
+import { useForm } from "react-hook-form";
+import { zodResolver } from "@hookform/resolvers/zod";
+import { z } from "zod";
+import { assignQuoteToLead } from "@/app/admin/leads/actions";
+import {
+  Dialog,
+  DialogContent,
+  DialogHeader,
+  DialogTitle,
+  DialogTrigger,
+} from "@/components/ui/dialog";
+import {
+  Form,
+  FormControl,
+  FormField,
+  FormItem,
+  FormLabel,
+  FormMessage,
+} from "@/components/ui/form";
+import { Input } from "@/components/ui/input";
+import { Button } from "@/components/ui/button";
+import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
+import { Loader2 } from "lucide-react";
+
+const assignQuoteSchema = z.object({
+  lead_id: z.string().min(1),
+  quote_token: z.string().min(1).optional(),
+  generate_new: z.boolean(),
+}).transform(data => ({
+  ...data,
+  generate_new: data.generate_new ?? false,
+}));
+
+export function SendQuoteModal({ leadId }: { leadId: string }) {
+  const [open, setOpen] = useState(false);
+  const [loading, setLoading] = useState(false);
+  const [tab, setTab] = useState<"existing" | "new">("existing");
+  const form = useForm<z.infer<typeof assignQuoteSchema>>({
+    resolver: zodResolver(assignQuoteSchema),
+    defaultValues: {
+      lead_id: leadId,
+      generate_new: false,
+    },
+  });
+
+  async function onSubmit(data: z.infer<typeof assignQuoteSchema>) {
+    setLoading(true);
+    try {
+      const result = await assignQuoteToLead({
+        ...data,
+        generate_new: tab === "new",
+      });
+      if (result.success) {
+        setOpen(false);
+        form.reset();
+      }
+    } finally {
+      setLoading(false);
+    }
+  }
+
+  return (
+    <Dialog open={open} onOpenChange={setOpen}>
+      <DialogTrigger asChild>
+        <Button variant="outline" size="sm">
+          Invia Preventivo
+        </Button>
+      </DialogTrigger>
+      <DialogContent className="max-w-md">
+        <DialogHeader>
+          <DialogTitle>Invia Preventivo al Lead</DialogTitle>
+        </DialogHeader>
+        <Tabs value={tab} onValueChange={(v) => setTab(v as "existing" | "new")}>
+          <TabsList className="grid w-full grid-cols-2">
+            <TabsTrigger value="existing">Preventivo Esistente</TabsTrigger>
+            <TabsTrigger value="new">Crea Nuovo</TabsTrigger>
+          </TabsList>
+
+          <TabsContent value="existing" className="mt-4">
+            <Form {...form}>
+              <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-4">
+                <FormField
+                  control={form.control}
+                  name="quote_token"
+                  render={({ field }) => (
+                    <FormItem>
+                      <FormLabel>Token Preventivo</FormLabel>
+                      <FormControl>
+                        <Input
+                          placeholder="Incolla il token del preventivo"
+                          {...field}
+                        />
+                      </FormControl>
+                      <FormMessage />
+                    </FormItem>
+                  )}
+                />
+                <p className="text-xs text-gray-600">
+                  Copia il token dal preventivo e incollalo qui. Il lead sarà aggiornato a "Proposal Sent".
+                </p>
+                <Button type="submit" disabled={loading} className="w-full">
+                  {loading && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
+                  Invia
+                </Button>
+              </form>
+            </Form>
+          </TabsContent>
+
+          <TabsContent value="new" className="mt-4">
+            <p className="text-sm text-gray-600 mb-4">
+              Crea un nuovo preventivo per questo lead. Ti reindirizzeremo al builder.
+            </p>
+            <Button
+              className="w-full"
+              onClick={() => {
+                window.location.href = `/admin/quotes/new?lead_id=${leadId}`;
+              }}
+            >
+              Apri Quote Builder
+            </Button>
+          </TabsContent>
+        </Tabs>
+      </DialogContent>
+    </Dialog>
+  );
+}