feat: lead → client conversion + client contact fields (email/phone)

Blocco A+B (milestone v2.3). Migration 0011 is additive (ADD COLUMN only):
clients.email, clients.phone, leads.archived.

- createClientCore() extracted from createClient and reused by conversion
- clients.email/phone added to create + edit forms and shown on client header
  (never exposed on the public /client/[token] page)
- convertLeadToClient(): reuses core, carries over lead transcripts
  (client_transcripts.client_id), links project.created_from_lead_id,
  archives the lead while keeping its "won" status; idempotent
- "Converti in cliente" button on won leads; "Convertito → Apri cliente"
  once converted (clientId resolved via created_from_lead_id)
- archived leads hidden from list/kanban; detail page fetches by id incl. archived

Migration must be applied to the prod DB BEFORE this is deployed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/admin-queries.ts

@@ -892,6 +892,7 @@ export async function getLeadsWithTags(): Promise<LeadWithTags[]> {
       next_action: leads.next_action,
       next_action_date: leads.next_action_date,
       notes: leads.notes,
+      archived: leads.archived,
       created_at: leads.created_at,
       updated_at: leads.updated_at,
       tag_name: tags.name,
@@ -904,6 +905,7 @@ export async function getLeadsWithTags(): Promise<LeadWithTags[]> {
         eq(tags.entity_type, LEADS_TAG_ENTITY)
       )
     )
+    .where(eq(leads.archived, false)) // converted leads are archived → hidden from pipeline
     .orderBy(desc(leads.updated_at), asc(tags.name));
 
   const leadMap = new Map<string, LeadWithTags>();
@@ -915,6 +917,54 @@ export async function getLeadsWithTags(): Promise<LeadWithTags[]> {
   return Array.from(leadMap.values());
 }
 
+// Single lead by id WITH tags — does NOT filter archived (the detail page must
+// still show a converted/archived lead).
+export async function getLeadByIdWithTags(leadId: string): Promise<LeadWithTags | null> {
+  const rows = await db
+    .select({
+      id: leads.id,
+      name: leads.name,
+      email: leads.email,
+      phone: leads.phone,
+      company: leads.company,
+      status: leads.status,
+      last_contact_date: leads.last_contact_date,
+      next_action: leads.next_action,
+      next_action_date: leads.next_action_date,
+      notes: leads.notes,
+      archived: leads.archived,
+      created_at: leads.created_at,
+      updated_at: leads.updated_at,
+      tag_name: tags.name,
+    })
+    .from(leads)
+    .leftJoin(
+      tags,
+      and(eq(tags.entity_id, leads.id), eq(tags.entity_type, LEADS_TAG_ENTITY))
+    )
+    .where(eq(leads.id, leadId));
+
+  if (rows.length === 0) return null;
+  let result: LeadWithTags | null = null;
+  for (const row of rows) {
+    const { tag_name, ...leadFields } = row;
+    if (!result) result = { ...leadFields, tags: [] };
+    if (tag_name) result.tags.push(tag_name);
+  }
+  return result;
+}
+
+// If this lead was converted, returns the client id of the project created from
+// it (projects.created_from_lead_id), else null.
+export async function getClientIdFromLead(leadId: string): Promise<string | null> {
+  const [row] = await db
+    .select({ client_id: projects.client_id })
+    .from(projects)
+    .where(eq(projects.created_from_lead_id, leadId))
+    .limit(1);
+  return row?.client_id ?? null;
+}
+
 export type LeadFieldOptions = { status: string[]; tags: string[] };
 
 export async function getLeadFieldOptions(): Promise<LeadFieldOptions> {