feat(04-01): multi-project schema migration — projects, settings, FK pivot

- schema.ts: add projects table, settings kv table, slug on clients;
  migrate 6 FK from client_id to project_id (phases, payments, documents, notes,
  time_entries, quote_items); update all relations and TypeScript types
- admin-queries.ts: fix getAllClientsWithPayments + getClientFullDetail to aggregate
  through projects; add getAllProjectsWithPayments, getProjectFullDetail,
  getClientWithProjects, ClientWithProjects type
- settings.ts: new file — getSetting, updateSetting, getTargetHourlyRate, SETTINGS_KEYS
- Fix all downstream files: actions.ts, quote-actions.ts, new/actions.ts,
  timer-actions.ts, approve/route.ts, comment/route.ts, TimerCell.tsx,
  analytics-queries.ts, client-view.ts, seed.ts
- DB migration applied to Coolify Postgres (all test data cleared, schema rebuilt)

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

src/app/admin/timer-actions.ts

@@ -2,12 +2,12 @@
 
 import { revalidatePath } from "next/cache";
 import { db } from "@/db";
-import { time_entries } from "@/db/schema";
-import { eq, isNull } from "drizzle-orm";
+import { time_entries, projects } from "@/db/schema";
+import { eq, isNull, asc } from "drizzle-orm";
 import { nanoid } from "nanoid";
 
-export async function startTimer(clientId: string): Promise<{ entryId: string }> {
-  // Stop any currently running session (for any client) before starting a new one
+export async function startTimer(projectId: string): Promise<{ entryId: string }> {
+  // Stop any currently running session before starting a new one
   const running = await db
     .select({ id: time_entries.id })
     .from(time_entries)
@@ -30,11 +30,23 @@ export async function startTimer(clientId: string): Promise<{ entryId: string }>
   }
 
   const id = nanoid();
-  await db.insert(time_entries).values({ id, client_id: clientId });
+  await db.insert(time_entries).values({ id, project_id: projectId });
   revalidatePath("/admin");
   return { entryId: id };
 }
 
+export async function startTimerForClient(clientId: string): Promise<{ entryId: string }> {
+  const projectRows = await db
+    .select({ id: projects.id })
+    .from(projects)
+    .where(eq(projects.client_id, clientId))
+    .orderBy(asc(projects.created_at))
+    .limit(1);
+  const projectId = projectRows[0]?.id;
+  if (!projectId) throw new Error("Nessun progetto trovato per questo cliente");
+  return startTimer(projectId);
+}
+
 export async function stopTimer(entryId: string): Promise<void> {
   const rows = await db
     .select({ started_at: time_entries.started_at })