feat(14-01): add updateLeadField and lead tag CRUD server actions

- requireAdmin() guard (mirrors catalog/actions.ts pattern), throws
  "Non autorizzato" before any DB access
- updateLeadField: EDITABLE_FIELDS allowlist, name/status validated
  server-side (LEAD_STAGES.includes), nullable fields cleared on empty
- addLeadTag/removeLeadTag/renameLeadTag: polymorphic tags table scoped
  to entity_type="leads" (LEADS_TAG_ENTITY), never touches
  entity_type="services" rows
- All four actions call revalidatePath for /admin/leads (+ detail page
  where a single leadId applies)
- Log pre-existing lint issues (unrelated to this task) to
  deferred-items.md per scope-boundary rule

src/app/admin/leads/actions.ts

@@ -2,11 +2,18 @@
 
 import { z } from "zod";
 import { db } from "@/db";
-import { leads, quotes } from "@/db/schema";
-import { eq } from "drizzle-orm";
-import { createLeadSchema, updateLeadSchema, createActivitySchema } from "@/lib/lead-validators";
+import { leads, quotes, tags } from "@/db/schema";
+import { eq, and } from "drizzle-orm";
+import {
+  createLeadSchema,
+  updateLeadSchema,
+  createActivitySchema,
+  LEAD_STAGES,
+} from "@/lib/lead-validators";
 import { revalidatePath } from "next/cache";
 import { createActivity, updateLeadStage } from "@/lib/lead-service";
+import { getServerSession } from "next-auth";
+import { authOptions } from "@/lib/auth";
 
 export async function createLead(data: z.infer<typeof createLeadSchema>) {
   const parsed = createLeadSchema.safeParse(data);
@@ -159,3 +166,95 @@ export async function assignQuoteToLead(data: z.infer<typeof assignQuoteSchema>)
     return { success: false, error: "Errore nell'assegnazione" };
   }
 }
+
+async function requireAdmin() {
+  const session = await getServerSession(authOptions);
+  if (!session) throw new Error("Non autorizzato");
+}
+
+// ── Inline-edit field update (Phase 14 database-view) ───────────────────────
+
+const EDITABLE_FIELDS = ["name", "email", "phone", "company", "status", "next_action"] as const;
+type EditableField = (typeof EDITABLE_FIELDS)[number];
+
+export async function updateLeadField(
+  leadId: string,
+  fieldName: EditableField,
+  value: string
+) {
+  await requireAdmin();
+
+  if (!EDITABLE_FIELDS.includes(fieldName)) {
+    throw new Error(`Campo non editabile: ${fieldName}`);
+  }
+
+  if (fieldName === "name") {
+    const s = value.trim();
+    if (s.length === 0) throw new Error("Nome richiesto");
+    await db.update(leads).set({ name: s, updated_at: new Date() }).where(eq(leads.id, leadId));
+  } else if (fieldName === "status") {
+    if (!LEAD_STAGES.includes(value as (typeof LEAD_STAGES)[number])) {
+      throw new Error("Stato non valido");
+    }
+    await db.update(leads).set({ status: value, updated_at: new Date() }).where(eq(leads.id, leadId));
+  } else {
+    // email | phone | company | next_action — nullable text fields, empty clears
+    const s = value.trim();
+    await db
+      .update(leads)
+      .set({ [fieldName]: s || null, updated_at: new Date() })
+      .where(eq(leads.id, leadId));
+  }
+
+  revalidatePath("/admin/leads");
+  revalidatePath(`/admin/leads/${leadId}`);
+}
+
+// ── Lead tags (Phase 14, CRM-09) — polymorphic `tags` table, entity_type="leads" ─
+
+const LEADS_TAG_ENTITY = "leads";
+
+export async function addLeadTag(leadId: string, value: string) {
+  await requireAdmin();
+  const trimmed = value.trim();
+  if (trimmed.length === 0) throw new Error("Valore richiesto");
+
+  await db
+    .insert(tags)
+    .values({ entity_type: LEADS_TAG_ENTITY, entity_id: leadId, name: trimmed })
+    .onConflictDoNothing();
+
+  revalidatePath("/admin/leads");
+  revalidatePath(`/admin/leads/${leadId}`);
+}
+
+export async function removeLeadTag(leadId: string, value: string) {
+  await requireAdmin();
+
+  await db
+    .delete(tags)
+    .where(
+      and(
+        eq(tags.entity_type, LEADS_TAG_ENTITY),
+        eq(tags.entity_id, leadId),
+        eq(tags.name, value)
+      )
+    );
+
+  revalidatePath("/admin/leads");
+  revalidatePath(`/admin/leads/${leadId}`);
+}
+
+export async function renameLeadTag(oldValue: string, newValue: string) {
+  await requireAdmin();
+  const next = newValue.trim();
+  if (next.length === 0) throw new Error("Nuovo nome richiesto");
+  if (next === oldValue) return;
+
+  await db
+    .update(tags)
+    .set({ name: next })
+    .where(and(eq(tags.entity_type, LEADS_TAG_ENTITY), eq(tags.name, oldValue)));
+
+  revalidatePath("/admin/leads");
+}