feat(registratura): atomic numbering, reserved slots, audit trail, API endpoints + theme toggle animation

Registratura module:
- Atomic sequence numbering (BTG-2026-IN-00125 format) via PostgreSQL upsert
- Reserved monthly slots (2/company/month) for late registrations
- Append-only audit trail with diff tracking
- REST API: /api/registratura (CRUD), /api/registratura/reserved, /api/registratura/audit
- Auth: NextAuth session + Bearer API key support
- New "intern" direction type with UI support (form, filters, table, detail panel)
- Prisma models: RegistrySequence, RegistryAudit

Theme toggle:
- SVG mask-based sun/moon morph with 360° spin animation
- Inverted logic (sun in dark mode, moon in light mode)

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

src/modules/registratura/components/registry-entry-form.tsx

@@ -15,6 +15,7 @@ import {
   Globe,
   ArrowDownToLine,
   ArrowUpFromLine,
+  ArrowRightLeft,
   HardDrive,
   FolderOpen,
   Link2,
@@ -554,6 +555,19 @@ export function RegistryEntryForm({
               <ArrowUpFromLine className="h-4 w-4" />
               Ieșit
             </button>
+            <button
+              type="button"
+              onClick={() => setDirection("intern")}
+              className={cn(
+                "flex flex-1 items-center justify-center gap-1.5 rounded-md px-3 py-2 text-sm font-medium transition-all",
+                direction === "intern"
+                  ? "bg-purple-500 text-white shadow-sm"
+                  : "text-muted-foreground hover:text-foreground hover:bg-background",
+              )}
+            >
+              <ArrowRightLeft className="h-4 w-4" />
+              Intern
+            </button>
           </div>
         </div>
         <div>