fix(04-06): five post-deploy fixes

- Middleware (proxy.ts): switch internal API calls to localhost instead of
  request.url — avoids Docker hairpin NAT issues where the container can't
  reach its own external hostname via Traefik
- ProjectRow timer: pass projectId={project.id} to TimerCell so it calls
  startTimer(projectId) directly instead of startTimerForClient(project.id)
- Admin client list: add slug field to ClientWithPayments + show slug link
  when available (falls back to token) — so admins see the human-readable URL
- Analytics contracted: sum projects.accepted_total (authoritative) instead
  of clients.accepted_total (always 0 in multi-project architecture)
- createClient: auto-generate slug from client name at creation time
  (e.g. "Mario Rossi" → "mario-rossi"), with -2/-3 suffix on conflict

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/analytics-queries.ts

@@ -4,8 +4,9 @@ import { sql, and, eq, inArray } from "drizzle-orm";
 
 export async function getAnalyticsByYear(year: number) {
   const [contracted] = await db
-    .select({ total: sql<string>`coalesce(sum(${clients.accepted_total}::numeric), 0)` })
-    .from(clients)
+    .select({ total: sql<string>`coalesce(sum(${projects.accepted_total}::numeric), 0)` })
+    .from(projects)
+    .innerJoin(clients, eq(projects.client_id, clients.id))
     .where(sql`extract(year from ${clients.created_at}) = ${year}`);
 
   const [clientsRow] = await db