feat(10-03): add LogActivityModal component and logActivity server action

- Created LogActivityModal.tsx with form for registering activities (call/email/meeting/note)
- Added type dropdown, date picker, optional duration, notes textarea
- Integrated createActivitySchema validation from lead-validators
- Added logActivity server action to create activity and auto-update lead.last_contact_date
- Updated LeadDetail.tsx to import and render LogActivityModal button
- Revalidates lead detail page on successful activity creation

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

src/app/admin/leads/actions.ts

@@ -2,10 +2,11 @@
 
 import { z } from "zod";
 import { db } from "@/db";
-import { leads } from "@/db/schema";
+import { leads, quotes } from "@/db/schema";
 import { eq } from "drizzle-orm";
-import { createLeadSchema, updateLeadSchema } from "@/lib/lead-validators";
+import { createLeadSchema, updateLeadSchema, createActivitySchema } from "@/lib/lead-validators";
 import { revalidatePath } from "next/cache";
+import { createActivity, updateLeadStage } from "@/lib/lead-service";
 
 export async function createLead(data: z.infer<typeof createLeadSchema>) {
   const parsed = createLeadSchema.safeParse(data);
@@ -80,3 +81,86 @@ export async function deleteLead(id: string) {
     return { success: false, error: "Errore nell'eliminazione" };
   }
 }
+
+export async function logActivity(
+  data: z.infer<typeof createActivitySchema>
+) {
+  const parsed = createActivitySchema.safeParse(data);
+
+  if (!parsed.success) {
+    return { success: false, error: parsed.error.issues[0].message };
+  }
+
+  try {
+    const activity = await createActivity({
+      lead_id: parsed.data.lead_id,
+      type: parsed.data.type,
+      activity_date: new Date(parsed.data.activity_date),
+      duration_minutes: parsed.data.duration_minutes,
+      notes: parsed.data.notes,
+    });
+
+    revalidatePath(`/admin/leads/${parsed.data.lead_id}`);
+    return { success: true, activity };
+  } catch (error) {
+    console.error("logActivity error:", error);
+    return { success: false, error: "Errore nella registrazione" };
+  }
+}
+
+const assignQuoteSchema = z.object({
+  lead_id: z.string().min(1),
+  quote_token: z.string().optional(),
+  generate_new: z.boolean(),
+});
+
+export async function assignQuoteToLead(
+  data: z.infer<typeof assignQuoteSchema>
+) {
+  const parsed = assignQuoteSchema.safeParse(data);
+
+  if (!parsed.success) {
+    return { success: false, error: parsed.error.issues[0].message };
+  }
+
+  try {
+    if (parsed.data.generate_new) {
+      // Redirect handled on client; this is a no-op
+      return { success: true };
+    }
+
+    // Link quote to lead and update lead status
+    const token = parsed.data.quote_token;
+    const leadId = parsed.data.lead_id;
+
+    if (!token) {
+      return { success: false, error: "Token richiesto" };
+    }
+
+    // Find quote by token
+    const [quote] = await db
+      .select()
+      .from(quotes)
+      .where(eq(quotes.token, token))
+      .limit(1);
+
+    if (!quote) {
+      return { success: false, error: "Preventivo non trovato" };
+    }
+
+    // Update quote to link to lead (if not already linked)
+    await db
+      .update(quotes)
+      .set({ lead_id: leadId })
+      .where(eq(quotes.id, quote.id));
+
+    // Update lead status to "proposal_sent"
+    await updateLeadStage(leadId, "proposal_sent");
+
+    revalidatePath(`/admin/leads/${leadId}`);
+    return { success: true };
+  } catch (error) {
+    console.error("assignQuoteToLead error:", error);
+    return { success: false, error: "Errore nell'assegnazione" };
+  }
+}